Impact of COVID-19 First Wave on Psychological and Psychosocial Dimensions: A Systematic Review

A systematic review of the literature investigating the effects of the COVID-19 pandemic on psychological and psychosocial factors was completed. Published literature was examined using electronic databases to search psychosocial factors such as beliefs and media persuasion, social support, coping, risk perception, and compliance and social distancing; and psychological factors as anxiety, stress, depression, and other consequences of COVID-19 that impacted mental health among the pandemic. A total of 294 papers referring to the first wave of the COVID-19 pandemic (December 2019–June 2020) were selected for the review. The findings suggested a general deterioration of mental health, delineating a sort of “psychological COVID-19 syndrome”, characterized by increased anxiety, stress, and depression, and decreased well-being and sleep quality. The COVID-19 effect on the psychological dimensions of interest was not the same for everyone. Indeed, some sociodemographic variables exacerbated mental health repercussions that occurred due to the pandemic. In particular, healthcare workers and young women (especially those in postpartum condition) with low income and low levels of education have been shown to be the least resilient to the consequences


Introduction
As of 21 February 2022, SARS-CoV-2 has infected more than 423 million individuals worldwide and caused more than 5.8 million deaths [1]. During the first months of 2020, the globe was under lockdown: the confinement measures which constituted an emergency protocol imposing restrictions on the free movement of persons [2]. These restrictive measures had various effects on people's daily life, and physical and mental health. This review arose from the need to summarize and schematize the many psychological publications related to the first wave of COVID-19, as they appear to be very large. The authors aim to provide a complete review of the literature on the psychological impact that the first wave (December 2019-June 2020) of COVID-19 had on a global level, to identify which factors related to the pandemic were most impacting people's mental health.
The results of the review regard the first wave of the pandemic (2019-2020). Therefore, this impact is unrepeatable in the future, also regarding resilience and transformative resilience. The findings could indicate a specific structure that could be attributed to a "psychological COVID-19 syndrome", characterized by symptoms relatable to anxiety, depression, stress, less wellbeing and more sleep problems.
We chose to analyze different variables of mental health studied in previous pandemics (Ebola, SARS, MERS, Novel influenza A, Equine influenza, etc.), in addition to psychosocial dimensions which proved to be essential to mitigate the spread of Coronavirus [3][4][5][6][7][8][9][10]. The authors decided to build on the dimensions considered in previous pandemics to observe whether these variables were also present in the current COVID-19 pandemic. For easy reading of the review, we divided the work into two sections: (1) Psychosocial Variables, and (2) Observables related with Mental Health.
For this systematic review, 294 articles published between December 2019 and June 2020 were analyzed, resulting in a large, heterogeneous literature, with a total sample of 732,852 subjects from more than 30 countries. Although the collected works are often based on non-representative samples, their large number and the possibility of cross-referencing the results common to these studies allows on the one hand to overcome the possible problem of unrepresentativeness, and on the other to grasp the existence of an effect, assuming the heterogeneity of the samples used by these works.
The authors hypothesize that from this systematic review can be derived the psychosocial and psychopathological areas most affected by the COVID-19 pandemic, and likewise, that can be delineated a profile of the most vulnerable individual to these types of issues. So, in this perspective, this review can be useful both for future research and for the current management of the pandemic emergency.

Review Methodology
In this section, details about the systematic review approach are provided. We relied on an adapted version of the systematic qualitative review approach by Higgins and colleagues [11]. The authors searched all the papers that included the relationship between COVID-19 and psychological variables of interest.
As a first step, we asked academic information specialists to search for COVID-19 scientific papers that fulfilled our inclusion criteria. These were: written in English language; published between December, 2019 and June, 2020; being an empirical study, project report or review; published in a scholarly peer-reviewed journal and/or conference proceedings; those related to psychological dimensions and mental health (i.e., psychological disorders, risk perception, beliefs, coping, compliance, social support). The specialists completed their task consulting the databases of PsycInfo, PsycArticles, PubMed, Science Direct, PsyArXiv, NCBI, medRxiv, and Elsevier repository. The authors on their part contributed to the search by consulting Google and Google Scholar to increase the chances of identifying the widest range of sources possible. The consultation took place between April and May 2020. A total of 7381 sources were considered. Subsequently, the authors' results were compared with those of the experts, and duplicates were removed. To select the papers, search terms such as "COVID-19", "Psychology", "Psychological", "Psychological effect", "Mental health" were included in the research. For a more complete list of all the search terms, see Appendix A. Based on the inclusion criteria, only 480 sources were accessed as full-text: 303 papers were eligible since they met the inclusion criteria.
At the title review stage, sources were most commonly rejected because they fulfilled two or more of the following exclusion criteria: were only citations, commentary, or books; were papers published before 2019; those not related to the psychological dimensions and mental health (i.e., psychological disorders, risk perception, beliefs, coping, compliance, social support); articles not in English language. At the abstract and full paper review stages, papers were most commonly rejected for: demonstrating no inclusion of a psychological variable, having incomplete results, using qualitative measures and articles where data analysis was not suitable for the systematic review process (e.g., lack of descriptive statistics, no correlation coefficients provided for the variables of interest).
A flow diagram of the systematic search is shown in Figure 1. This review is divided into two main sections: (1) Psychosocial Variables , and (2) Observables related to Mental Health. The first section is in turn divided into different subsections: Beliefs and Media Persuasion, Social Support, Coping, Risk Perception, and Compliance and Social Distancing. The second section is in turn divided into different subsections: Anxiety, Stress, Depression, and Other consequences of COVID-19 on Mental Health. These are the dimensions that emerged most during the analysis of the literature about COVID-19. The subdivision in these paragraphs was formulated to make reading easier. Every subsection is divided into "Introduction ", "Measures", and "Results".
Postponed to the "Discussion" paragraph is the possibility of connecting in a single design all the results emerging from the various sections, towards a definition of a psychological COVID-19 syndrome. For an easier reading, you can consult Table A1 (placed in the Appendix A) that contains the main information of the papers analyzed.

Introduction
Probably the most important factor determining the resilience of a human community exposed to a pandemic is the readiness to change habits in order to face the diffusion of the virus [12][13][14][15]. Of course, the role of information spreading about the pandemic was a fundamental factor to promote such a change, even if the impact of the communication style, source of information and other elements should also be taken into consideration in order to maximize the impact of the media on the people's beliefs and behaviours [12][13][14][15].
In particular, literature reports studies examining why some people believe in conspiracy theories about COVID-19, and why they choose to not follow the rules/laws given by the government to prevent contagion. Uncertainty and ambiguity regarding the information about COVID-19 could lead to a lack of trust in governmental regulations, bringing people to respond with adaptive or non-adaptive coping strategies [16]. Some studies investigated how people were influenced by the media (both traditional and new media), and how disinformation may be enhanced by the possibility offered by the new media to share an opinion about medical topics without the proper knowledge, widely spreading conspiracy theories [17]. Clearly, the distrust in science and in the medical system could increase the risks [18]. Table 1 shows the validated measures used to analyze "Beliefs" and "Media persuasion". About "Media persuasion", all articles [17,[19][20][21][22][23][24] used ad-hoc measures. Table 1. Validated tools to measure "Beliefs" and "Media persuasion". In the table are reported the psychological tools adopted by the studies taken into account, their internal consistency (reliability), and their frequency.

Result for Beliefs and Media Persuasion
The results of the articles reviewed on beliefs and media persuasion were distinguished by the authors into three main categories considering three fundamental moderators: attitudes, scholarship and scientific knowledge, finding news on social networks.
Conspiracy theories: With regard to conspiracy theories, some studies show that subjects who believed that COVID-19 was a hoax complied less with the suggested behaviour to reduce and contain the infection. Moreover, it was seen that these subjects engaged more in self-centred behaviour aimed at personal benefit during the crisis (e.g., hoarding everyday goods, relying on "alternative" sources of information) than in reducing the infection rate (e.g., increased hygiene behavior, keeping physical distance to others) [18]. It has been seen that a high level of collective narcissism (inflated belief in the greatness of one's ingroup) is related to a greater agreement with conspiracy theories [50]. In addition, those who support conspiracy theories may be less likely to get vaccinated if this will be available [51,52]. With regard to the sharing of conspiracy theories related to COVID-19, it was seen that individuals with high levels of Social Dominance Orientation and low levels of Traditionalism were more likely to spread them, but were less likely to share misinformation about the severity and spread of COVID-19 [53]. There are socio-demographic differences: the more religious and/or politically right-wing subjects were inclined to believe in conspiracy theories [48]. In conclusion, the convictions of conspiracy theories related to COVID-19 were strongly correlated with convictions of broader conspiracy theories and a lower level of education, and weakly correlated with more negative attitudes towards the government [46].
Finally, even the communication style affected the attitudes and behaviours of people around the world. Research about media persuasion found that fear messages create a stronger emotional reaction than the prosocial message, but the prosocial message was more effective in increasing the desire for self-isolation if it produces a strong emotional response. Both fear and prosocial messages were equally effective in stimulating a willingness to engage in preventive behaviors [20]. In conclusion, situational awareness (a construct based on SAT-Situational Awareness Theory; a sort of perceived understanding) influenced social distancing. The sources of information, formal and informal, were found to be significantly correlated with situational awareness [22], in particular public health officials or high-power political figures may be more persuasive [19]. Table 2 shows information about the papers analyzed for the study of Beliefs and Media persuasion. Table 2. Beliefs and Media Persuasion. Summary of sources, with the number of papers analyzed, the total sample size, the provenance of the sample and the mediator variables. *: "MTurk" is used to indicate a sample extended worldwide.

Beliefs and Media Persuasions
Valid papers 36 Sample size 50,090 Table 4. Social support. Summary of sources, with the number of papers analyzed, the total sample size, the provenance of the sample and the mediator variables. "MTurk" is used to indicate a sample extended worldwide.

Social Support
Valid papers 16 Sample size 69 In the scientific literature, one of the most important factors that can buffer the effects of a stressful situation, such as COVID-19, is the coping that people implement to deal with new difficulties [72,73]. Coping refers to the effort to solve personal and interpersonal problems in order to master, reduce or tolerate stress and conflicts [71,74], or in other words, "the thoughts and actions that individuals use to deal with stressful events" [72]. Two general coping strategies are traditionally identified by the literature: (i) problem-focused coping, which concerns solving the problem or taking action to change the situation (active coping, planning, and use of instrumental support), (ii) emotion-focused coping, which aims to reduce the emotional distress (use of emotional support, acceptance, positive reframing, religion, humor, substance use, self-distraction, self-blame, denial, behavior disengagement, and venting) [72,74]. The scientific community also distinguished between coping with a positive or negative outcome [71]. Negative coping strategies are considered primary risk factors, and are associated with depression, anxiety and stress [55,73,75]. Conversely, positive and adaptive coping styles can protect individuals' mental health [75][76][77], and enhance their capability to deal with challenges [76,78] such as those related to COVID-19 [78,79]. Table 5 shows the validated measures used to analyze "Coping". Table 5. Validated tools to measure "Coping". In the table are reported the psychological tools adopted by the studies taken into account, their internal consistency (reliability), and their frequency.

Results for Coping
In general, positive coping strategies (e.g., active coping, use of emotional support, humor, mindfulness) appeared related to lower levels of psychological distress in the pandemic scenario [71,72,79] and higher well-being [77,91]. Specifically, high self-control perception, acceptance, behavioral activation, and values-based action strategies resulted in lower levels of fear, restlessness, trouble relaxing, and general vulnerability [76,88]. Moreover, Meaning in Negative Experiences (i.e., the general positive beliefs about negative experiences and the tendency to actively reflect on their meaning or value), was associated with a higher risk perception that may help people in dealing with anti-covid behaviors more successfully [92].
Nonetheless, the outcomes of problem-oriented coping strategies appeared nondefinitive. Indeed, problem-oriented coping strategies were found to be associated with higher levels of fear, anger, and psychological distress [72,79]. Negative (emotional-focused) coping was associated with high psychological distress [71], anger [72], and perceived stress [55,74]. Negative coping strategies, like excessive cleaning, reassurance seeking, and excessive checking, were associated with higher levels of irritability and fear [88].
In two recent works [8,93], the most commonly used strategies for coping were: use of emotional support, planning, accepting the situation, learning to start living again, and religious/spiritual strategies. On the contrary, the most rarely used strategies were: substance use, denial of the fact of a difficult situation, behavioral disengagement, and self-blaming for the situation [93]. Those with suspected infection rarely used any coping style to deal with stress, but spent more time searching for information about COVID-19 and received less social support [71].
Coping strategies used during the pandemic were associated with age, gender, sociodemographic, and psychological variables. The results are shown below.
Gender: Females tended to use more strategies focused on emotions, such as distraction, emotional and religious support and less use of humor [89], but also problem-focused coping strategies [72].
Comorbidity: Anxiety was negatively associated with total coping strategies [94], especially with problem-focused coping strategies [72]. Table 6 shows information about the papers analyzed for the study of coping. Risk perception is defined as one's assessment of hazardous objects or activities [95][96][97] and it is composed of perceived susceptibility and severity [98,99]. During the COVID-19 research, the first referred to beliefs about the possibility of contracting the disease, while the second referred to beliefs about the severity of the disease [98,99]. It is important to remember that risk perception is based on personal judgements, and not on real features of the risk [25]; for this reason, risk perception increased with dread, lack of control and unknown risk [100]. Results reported that the greater the perceived risk by an individual, the greater the motivation to adopt protective behaviors (e.g., hand washing, avoiding hand shaking, maintaining social distancing) [40,48,95,98,[101][102][103][104][105][106][107]. As claimed by the Extended Parallel Process Model [108], it is not significant to have a high or low level of risk perception, but it is necessary to have an optimal perception (supported by self-efficacy, susceptibility, severity, and response efficacy), such as to trigger compliance with the rules.
Unfortunately, the perception of personal risk and threat appeared as not sufficient to trigger enough protective behavior during the COVID-19 pandemic: if the only determinant factor of protective behavior was the perception of the threat, only a few individuals were persuaded and consequently compliant [102]. The risk perception of being infected by COVID-19 was also affected by the type of information that the individual received by the media [25,109,110], by the lack of trust in official guidelines [16], and by the frequent exposure to information [111]. A good communication of information about the pandemic resulted in better preventive behaviors [101], because the severity and the perceived risk of getting infected by COVID-19 appeared as inducing belief in conspiracy theories [39,48]. These irrational beliefs provided a defense against external and unknown events, like the COVID-19 pandemic, and they were associated with negative health behaviors [39]. Indeed, conspiracy theories could persuade people to not follow preventive measures; in this case, a higher risk perception appeared to remove this effect [103].
Finally, socioeconomic and demographic variables (e.g., living alone, living with children), living in high risk areas, and contact with individuals infected by the virus, appeared to modify people's risk perception [112,113]. Risk perception during the COVID-19 first wave was also positively associated with psychosocial distress [111], anxiety [37,40], depression [37] and PTSD [37].
Only two studies [111,130] used already validated measures to assess risk perception (Table 7). Table 7. Validated tools to measure "Risk perception". In the table are reported the psychological tools adopted by the studies taken into account, their internal consistency (reliability), and their frequency.

Results for Risk Perception
Although COVID-19-related risk perception increased from March to April 2020, many people underestimated the risk of the disease [16,39,99,124]. A lower risk perception may lead to a lower level of compliance with health-protective behaviors [37,39,95,102,107,122,124,126], like hand-washing [105,122], social distancing [25,95,105,116,122] and mask-wearing [25,120].
According to Globis and colleagues, and Marotta and colleagues [119,130], during the lockdown period in the USA and Italy, people reported a lower perception of COVID-19 infection risk, probably due to the government's imposition of social distancing [119,130]. A greater knowledge about the prevention and transmissibility of COVID-19 was associated with lower levels of perceived risk [129]. Conservatorism tended to be associated with lower risk perception as well [128]. Risk perception could also be influenced but in a different direction (i.e., positively) by media accuracy [128], exposure to COVID-19 news [111], using social media [109], and collective orientation [118]. Belief in conspiracy theories was also associated with greater risk perception of contamination [48,103].
Contrary to expectations, risk perception of COVID-19 was not influenced by the existence of previous pathologies [79]. Risk perception levels appeared to play a role in the coping strategy that individuals used to deal with the pandemic. Perceived high threat was linked to a higher level of meaning in negative experiences (MINE) [92], while low risk perception was associated with a higher use of COVID-19 humor [115].
Finally, a strong predictor of risk perception was the work: healthcare workers showed higher risk perception than other participants [78,127], especially those who have longer shifts [112].
Risk perception during the pandemic was associated with age, gender, culture, and psychological variables. The results are shown below.
Age: Age was found to be an important predictor of risk perception [40,113]. However, the data showed conflicting results. Some research showed that younger people report higher perceived risk [107,112]. On the contrary, other studies found that the likelihood to feel threatened increased significantly with age, in other words, older adults perceived more risk of COVID-19 than younger people [16,114,117,120].
Gender: Women reported higher levels of risk perception compared to men [104,107,113,114,117,127]. Moreover, by analyzing the interaction effect between gender and age, Iorfa and colleagues [121] found that older men reported a higher risk perception than younger men [121].
Culture: The levels of risk perception reported in different parts of the world, apart from possible cultural factors, appeared to be affected by the levels of contagion. For instance, people residing in Europe reported lower levels of perceived threat than people residing in North-America [117]. Participants that lived in central and northern Vietnam reported a lower risk perception of COVID-19 than those who lived in southern Vietnam (that is also preferred by Chinese tourists) [109]. This trend is also detectable within the same country if the contagion was not homogeneous. For instance, people living in northern Italy reported more preoccupation about risk of infection than those who live in the center and south Italy [78,127].
Comorbidity: The perceived severity of COVID-19 was positively associated with mental health problems [76,125]. Higher levels of risk perception of COVID-19 were associated with depression [96,129,133], anxiety [37,96,106,110,118], and stress [118,127,133], but also with death anxiety [127] and coronavirus fear [133]. Table 8 shows information about the papers analyzed for the study of risk perception. Governments around the world adopted prevention guidelines (suggested by the World Health Organization, WHO, and the Centers for Disease Control and Prevention, CDC) to contain the spread of COVID-19 [134,135]. The effectiveness of these measures depend mostly on the compliance of the population [135], while the adherence to these relied on how much they were perceived as effective [136,137]. Adopting preventive measures is crucial to control the virus' spread and limiting its consequences [125,136,138,139]. Some of these procedures were enforced by states (e.g., closure of public places), whereas other procedures were only advised but out of the state's control (e.g., social distancing, hand washing) [139]. Many of these rules and recommendations can be considered as fairly drastic for citizens [140]. For this reason, some people ignored these instructions, exacerbating the problem [134]. Despite the importance of these rules, such as social distancing, compliance has been sometimes inadequate [141]. Social distancing was defined by CDC as "keeping space between yourself and other people outside of your home by staying at least 6 feet from other people, refraining from gathering in groups, and staying out of crowded places and avoiding mass gatherings" and seems to be the best way to limit the COVID-19's spread [141]. Nevertheless, social distancing may lead to self-isolation, which could cause severe psychological consequences [125]: for example, increased loneliness is associated with suicidal ideation and parasuicidal behavior, depression, anxiety, etc [138]. Although there are positive consequences for the public good, it is often a burden for the individual to adopt these preventive measures [136], because it is undeniable that COVID-19 restrictions could lead to drastic changes in daily life, including potential mental health problems [137].
The already validated questionnaires used to measure compliance and social distancing are reported in Table 9. Table 9. Validated tools to measure "compliance and social distancing". In the table are reported the psychological tools adopted by the studies taken into account, their internal consistency (reliability), and their frequency.

Results for Compliance and Social Distancing
The results of the articles reviewed on compliance and social distancing were distinguished by the authors into the two main themes.
Compliance: The first aim of the COVID-19 guidelines was to help slow the spread of the virus, prevent infections, and the consequent depletion of medical structures, supplies, and healthcare personnel [144]. The most implemented protective behaviors were: social distancing, washing hands, avoiding contact, avoiding crowded places, mask and gloves wearing, staying at home as much as possible, avoiding public transportation [16,52,119,136,155,157]. Compliance with these behaviors was positively associated with the fear of COVID-19 [169,170,178], trust in the government [154,164], risk perception [48,104,134,137], trust in science [134,179], feeling of safety [137], perspective taking (i.e., the tendency to look at things from other people's point of view) [90], and disgust towards pathogens [90]. On the contrary, conspiracy theories [18,45,90,103,167], impulsivity [48], self-centered behaviors [18,49,136], outdoor sports [104] and low conscientiousness score [146] were negatively associated with the adherence to the preventive behaviors. Moreover, communication appeared essential to enhance people's compliance. Specifically, by giving detailed information, underlining the impact of non-adhesion to anti-contagion rules, and adhesion benefits, compliance increased [101,144,147,158].
Finally, people who agreed more with anti-covid restrictions [179], were more motivated [150], and had a positive evaluation about how institutions manage the pandemic crisis [165], complied more.
Compliance during the pandemic was associated with age, gender, social condition and psychological variables. The results are shown below.
Age: Age was positively associated with compliance intentions [154]. In general, older individuals appeared as more willing to accept anti-COVID-19 restrictions [140,142]. Nonetheless, results were contradictory: some research [89,101,119,179] showed that older citizens tended to be more (self-declared) compliant; but others demonstrated that young adults complied more with prevention measures (e.g., cell phone disinfection, maintaining a safe distance) [143,160,162,166]. Finally, one research showed that different age ranges followed different protective behaviors. Younger respondents avoided hugging and kissing with family members, friends and acquaintances, respected more movement restrictions and avoided contact with the elderly; differently, the elderly avoided more shaking hands, they maintained the recommended distance more strictly, disinfected their pets' paws more often, and made more dietary plans [40].
Gender: Most of the papers that have investigated this topic agreed that women showed more compliance than men to protective behaviors (e.g., wearing mask, do not touch their face, do not shake hands) [40,66,98,101,119,139,152,154,160,161,179]. Females compliance seemed to be influenced by four internal sources: health history, anxiety, feeling responsible for others, feeling responsible for oneself [161].
Social Condition: the results about social conditions were conflicting. Some papers [40,152,179] found that a higher level of education was associated with more compliance to the prescriptions (e.g., avoid hugging and kissing, use disinfectants, avoid shaking hands). Other papers [101,160] instead found the contrary (high levels of education led to less adherence to the rules).
Comorbidity: according to some papers [148,156], anxiety could be a predictor for the adherence to COVID-19 prescriptions, in fact anxiety seemed to lead individuals to more responsible behavior [148]. Interestingly, adhering to anti-COVID-19 prescriptions seemed to lower Coronavirus anxiety levels [38], and decrease suicidal ideation, negative thoughts and sleep disorders [153]. Moreover, the use of personal measures of prevention (e.g., washing hands, mask wearing) were associated with less severe psychiatric symptoms [168]. Finally, people with chronic health conditions implemented more safety behaviors [180].
Social Distancing: Social distancing was one of the most important and effective measures to fight the COVID-19 pandemic worldwide [159] and was always highly recommended by governments and by WHO. The compliance with social distancing was associated with outcomes like boredom and loneliness, and was achieved by people with a higher self-control [135,159]. Loneliness due to social distancing was particularly high in those who were single, who had a psychiatric diagnosis, and those who ruminated and worried more [125,138]. Furthermore, many people perceived "social isolation fatigue", that was increased by negative surprises (i.e., lockdown measures will be in effect for a longer time than expected) [145]. In fact, according to Briscese et al. [145] and Gollwitzer et al. [151], the intention to social distance weakens with time (due to habituation).
Some of the strongest predictors of social distancing behavior were related to COVID-19 related risk perception, knowledge and beliefs [141]; respondents who were more likely to comply with social distancing included those who believed they could help prevent the spread of COVID-19 [141,151], had higher risk perception [95,116,141,179], perceived their communities were adhering [141,149], knew COVID-19 information [141,151]. Other factors that resulted in a positive association with social distancing compliance were higher financial stability [141,181], negative illness attitude [143], used analytic thinking (deliberative, cognitively-demanding and slow) [167], and had higher FFFS (fight-flight-freeze system) scores (reflecting fear/avoidance behaviors) [143].
According to Charles and colleagues [141], even though 87.5% of the population had high levels of knowledge about social distancing, only 46.2% always practiced it. Those who perceived social distancing as difficult [141], those who did not like the spokesperson of preventive health behaviors [142], those who were still working [141,151], those who reported more conflicts with their partner [181], and impulsive [179], conservative [128,149] and self-centered people [49] were less likely to comply. In terms of personality, low extroversion [146], high agreeableness [171], and high conscientiousness [95,146,171] predicted the approval of social distancing measures. The motivation to adhere to social distancing rules was affected by empathy [163] and altruism [182]. Finally, humor could be useful to defuse the situation during the lockdown [115].
Social distancing during the pandemic was associated with age, gender, social condition and psychological variables. The results are shown below.
Age: For age, the results showed that younger people were most likely to follow the guidelines, especially social distancing [143].
Gender: According to several pieces of research [89,95,141,161,179], women were more likely to comply with social distancing than men.
Social Distancing: For the social condition, conflicting results have been found. Charles and colleagues [141] found that low-income respondents were more likely to comply with social distancing than those with a higher income [141]. On the contrary, the results of Farias and colleagues [149] showed the lower the income was, the less compliance with social distancing was observed [149].
Comorbidity: According to Hoffart and colleagues [138], social distancing was significantly associated with depression and anxiety [138]. Table 10 shows information about the papers analyzed for the study of compliance and social distancing. Table 10. Compliance and Social Distancing. Summary of sources, with the number of papers analyzed, the total sample size, the provenance of the sample and the mediator variables. "MTurk" is used to indicate a sample extended worldwide. We chose to analyze anxiety because research on past epidemics, like SARS, MERS, swine flu and Ebola, revealed a wide range of negative psychosocial impacts, of which anxiety was one of the main outcomes [7,37,[183][184][185][186]. In particular, the quarantine had a huge impact on people: when comparing quarantined versus non-quarantined individuals, the first were more likely to show psychological distress and to have a high prevalence of psychological symptomatology [187]. A recent study about the COVID-19 emergency indicated that "53.8% of respondents rated the psychological impact of the outbreak as moderate or severe; (. . . ) 28.8% of respondents reported moderate to severe anxiety symptoms" [186].

Compliance and Social Distancing
Additionally, uncertainty may exacerbate the already existing detrimental effect of the pandemic on anxiety [188]. Anxiety is not just an outcome of the pandemic but could also have repercussions on behaviours implemented during the pandemic.
In the work of [185], it emerged that high and low anxiety individuals [189] behaved differently on some specific COVID-19 related conducts. High anxiety individuals may cause crowding (and thus increase the likelihood of infection), but at the same time they may be reluctant to seek medical assistance for fear of transmission, whereas individuals with low anxiety were found reluctant to comply with preventive measures [185].

Measures
The already validated questionnaires used to measure anxiety are reported in Table 11. Table 11. Validated tools to measure "Anxiety". In the table are reported the psychological tools adopted by the studies taken into account, their internal consistency (reliability), and their frequency.

Results for Anxiety
Fitzpatrick et al. (2020) [212] and Guo et al. (2020) [213] highlighted high and medium levels of anxiety in the USA and China populations. Pandemic related distress was associated with anxiety: specifically, perceiving symptoms of COVID-19 (fever, cough, etc.), loneliness and stress increased anxiety levels [214,215].
Following protective measures, like mask-wearing and handwashing, were related to lower anxiety levels [23,168,216]. Nonetheless, adopting these protections appeared as not enough for drastically lowering anxiety; instead, adhering to social isolation policies appeared as essentials to reduce anxiety levels [38].
Individuals with a higher level of COVID-19 knowledge were more likely to report a higher level of anxiety [16,23,41,157], but, despite this, up-to-date and accurate health information, along with being aware of the risks of the pandemic, were protective factors against the pandemic's psychological burden [186,226]. The exposure time to COVID-19 information was associated with greater anxiety levels [211,216,226,227], as well as worries and concerns about COVID-19 [37,118,223,228,229].
Risk perception also played a role in shaping people's anxiety in the pandemic scenario. Indeed, people who perceived a high risk and a realistic high threat reported higher levels of anxiety [6,96,122,133,230].
Anxiety was also studied and investigated in some specific populations, like medical-care workers. Several papers analyzed samples composed healthcare personnel (doctors, nurses, physical therapists etc.), finding a high prevalence of anxiety symptoms [70,157,220,222,[231][232][233][234][235]. Although, according to [8], there was no significant difference in anxiety levels among doctors, nurses and pharmacists. Instead, the essential aspect that appeared to affect healthcare personnel anxiety levels is the time spent in the hospital [72]. In addition, healthcare workers who believed the virus was developed in a lab reported higher levels of anxiety [235].
Anxiety levels during the pandemic were associated with age, gender, social condition, socio-demographic variables, culture and psychological variables. The results are shown below.
Social Condition: Several studies have shown that a higher level of education is correlated with an increased anxiety about COVID-19 [67,201], particularly individuals with a lower level of education than middle school are more anxious [224]. Other studies show that high levels of anxiety appear to be income-related: lower income leads to higher levels of anxiety [187,233,248,256].
Socio-demographic variables: Research shows that unemployment, self-employment, private sector employment, lack of formal education, family size, and paternity (>2 children) were associated with a higher likelihood of negative mental health [247]. The confidence in the physician's ability to diagnose COVID-19 infection, the decrease in the probability of contracting it and the lower frequency of seeking information about it, because of satisfaction with the information received, have been protective factors against negative mental health, like anxiety [247]. Another protective factor against COVID-19 anxiety is living in urban areas and living with parents [58]. Instead, longer working time and more years of work increased the risk of anxiety [220,261]. Finally, living in heavily crowded areas, where the social distancing requirements are lacking, could lead to higher levels of anxiety [264]. Students, especially abroad ones [54], experienced relatively greater anxiety during the period of the epidemic [7,265], except if they considered themselves healthy [155]. Research has also observed that levels of anxiety among medical students have decreased with the introduction of distance learning [37].
Culture: Only Liu et al. [24] investigated and found significant differences possibly due to culture diversity. In their study, Asian Americans, Hispanic/Latinos reported lower anxiety levels than Whites [24].
Comorbidity: Anxiety measured during COVID-19 epidemic showed different comorbidity effects [55,56,58,67,70,221,229,262,[266][267][268]. People with psychological anxiety disorders appeared more vulnerable to the impact of the COVID-19 epidemic on their mental health in terms of well-being and quality of life [220,221]. Anxiety during the COVID-19 epidemic was associated with negative affect [269], PTSD symptoms [268] and risk of postpartum depression [266,267]. The well known relationship between anxiety and sleep disorders [188] seemed to be confirmed also about Coronavirus specific anxiety. Indeed, Coronavirus anxiety levels were higher in people with sleep disorders (like insomnia) and poor sleep quality [70,99,188,227,[270][271][272]. Only one article [273] found no significant correlation between anxiety and sleep disorders. Table 12 shows information about the papers analyzed for the study of anxiety.

Introduction
The COVID-19 outbreak has caused public panic and mental health stress [10]. McEwen and colleagues [274] defined stress as an adaptive psycho-physical reaction in response to a physical, social or psychological stimulus, called a "stressor". Stress-related responses are cognitive, emotional, behavioural and physiological [74,275]. During the first wave, the pandemic had an unprecedented impact on social lives around the world and can be viewed as a global stressor induced, beyond the risk for health, by the social isolation and distancing measures [276][277][278]. There is a lack of psychological literature related to epidemics (e.g., Ebola, Swine flu) or global pandemics; the last pandemic was the Spanish Flu of 1918, but there is not enough research about this [6]. The few recent studies about epidemics noted that there was increased stress due to the epidemic and quarantine [247]. Quarantine has been associated with high stress levels, depression, anxiety, irritability, insomnia, burnout, and physical symptoms [6,38,75,225,279]. Furthermore, being quarantined is associated with acute stress and trauma-related disorders, like Post Traumatic Stress Disorder (PTSD) [57,75,225,[280][281][282][283]. In particular, during the first wave of COVID-19, PTSD appeared as characterized by involuntary memories of the trauma such as intrusions or nightmares, persistent avoidance of stimuli associated with the traumatic event, negative alterations in cognitions and mood that are associated with the trauma, as well as alterations in arousal and reactivity that are associated with the trauma [281,283]. Those populations who were more at risk, such as health workers, were more likely to develop this kind of disorder [10,57,225,284].
Moreover, the disruptive changes of the work market also led to higher general levels of stress [285]. For instance, many people had lost their jobs because of the pandemic, others had to work from home while taking care of the family (i.e., remote working) [7], especially teachers who were forced to rely on information and communication technology (ICT) despite their technological literacy and/or fluency [286]. In particular, this pandemic seemed to psychologically affect healthcare providers and other workers, since they were on the front line [284]. Additional factors that seem to exacerbate stress levels in the population during isolation or quarantine [287] were an incorrect perception about the transmission of the virus [288] and conspiratorial beliefs [46].

Measures
The validated questionnaires used to measure stress are reported in Table 13. Table 13. Validated tools to measure "Stress". In the table are reported the psychological tools adopted by the studies taken into account, their internal consistency (reliability), and their frequency. 1: Modified version of PTSD Checklist for DSM-5 [289]; 2: adapted from the 14-item Perceived Stress Scale [290].
Interestingly, using the internet was positively associated with higher levels of stress [183,226,269,309]. For example, some studies showed that the use of social media (during the pandemic) was associated with symptoms of PTSD [183], because on these platforms there was information available that is not necessarily based on well-founded facts [226]. This could lead to confusion and uncertainty among individuals about the preventive measures taken to reduce the spread of the COVID-19 virus. The minimisation and unacceptability of the severity of the COVID-19 pandemic has been associated with stress [226]. When people reported more stress related to COVID-19, they felt less satisfied, less engaged, and more conflicted in their relationships [181]. For example, one study [7] saw how those who had a relationship without cohabitation perceived more individual and relational stress during lockdown [7].
The category of healthcare workers reported higher levels of stress [127,220,221,254,260,268,281,288]; and in particular, females reported to be more stressed than males [168,220,314]. According to [87], the main factors associated with stress were: concerns for personal safety, concerns for their families, and concerns for patient mortality; the factors that reduced stress were: correct guidance, and use of protective behaviors for prevention.
Stress levels during the pandemic were associated with age, gender, social condition, culture and comorbidity. The results are shown below.
Age: results showed a significant impact of age on stress levels [74]. A lot of papers reported higher stress and PTSD levels among the younger individuals rather than the older one [7,75,118,187,243,247,258,260,277,308,[317][318][319][320]. These results are not found within the medical staff sample [87].
Gender: numerous articles have reported a significant relation between gender and stress, with females reporting higher levels of stress and PTSD than males [10,74,186,187,220,221,225,237,242,243,247,252,259,260,277,281,282,309,317,[319][320][321][322], in particular, women who have been in direct contact with a COVID-19 patient [260], or those who have a recent exposure history in Wuhan [282]. Accordingly to Newby and colleagues [310], not only women, but also those who identify as non-binary or with a different gender were associated with higher self-reported stress. Finally, Cai and colleagues [87] found that factors that could reduce stress (i.e., correct guidance and effective safeguards for prevention from disease transmission) had a larger impact on females than males.
Social Condition: people with lower education experienced higher levels of stress [74,252]. Regarding the difference between occupations, those who had undergone the greatest change in work, like medical staff and teachers, showed themselves as the most stressed [275,286,288]. Indeed, teachers and healthcare workers continued to work in emergency circumstances. Unemployment and discontinued working activity (working more) were also associated with higher stress [7,225,247,309]. Finally, lower incomes [56,233,247], student status [186,265,269,308,323], marital status [247,317], large families [74,317], and more years of working [220] were associated with more stress.
Culture: Geographical differences in the effect of the pandemic were few and fragmentary, but are reported below. Italian, Chinese, Nigerian and Aboriginal populations reported high prevalence of stress symptoms [231,280,310]. Australians were more stressed than the Chinese population, but less than Italians [256]. The Austrian population was less stressed than the Chinese population [226].
Comorbidity: During the COVID-19 pandemic, a significant positive correlation was observed between stress and depression [251,309,312], anxiety [251,312], sleep [283], physical illness [220,262,310,320,324], somatization [312], and history of mental disorders [220,259,310]. Table 14 shows information about the papers analyzed for the study of stress. Depressive disorder affects thoughts, emotions, and physical health to varying degrees [325], and it often manifests as low mood, slow thinking, decreased activity, and impaired cognitive function [253]. The consequences are quite serious, ranging from interruption of interpersonal relationships to lifelong mental illness and suicidal behavior [78,253,312,326]. Previous public health pandemics have been linked to an increase in mental health problems. For example, Ebola, SARS, MERS, novel influenza A, equine influenza outbreak seemed to be associated with higher levels of depression [4,6,157]. In line with previous epidemics, the COVID-19 pandemic showed a similar effect on depression [212,222,223,272,304]. In particular, quarantine and social isolation, but also the strict prevention and control requirements, and the patients' lack of communication with the outside world, were associated with higher rates of psychological depressive symptoms [78,185,187,214,216,223,245,251,321,327].
The pandemic not only elicited symptoms of psychological distress in people with no previous history of depressive symptoms, but also worsened them in people with a history of psychiatric disorders such as depression [78,326]. Another source of depression symptoms was individuated by the literature in the constant exposure to information about COVID-19 [185,216], combined with the uncertainty of the situation [185,251,312]. Just one of 97 papers did not capture effects of the pandemic on depression levels [214].

Measures
The already validated questionnaires used to measure depression are reported in Table 15. Only two studies used ad hoc questionnaires to analyze depression [328,329]. Table 15. Validated tools to measure "Depression". In the table are reported the psychological tools adopted by the studies taken into account, their internal consistency (reliability), and their frequency.

Results for Depression
The influence of COVID-19 on depression levels is not solely attributable to the factors outlined in the introduction. There were a number of dynamics that still impact depression and were increased during the pandemic [6,212,259,310,328]. Among these factors were those related to aspects strictly connected with COVID-19 [24,111,133,157,214,215,220,225,240,243,269,[345][346][347], risk perception and its reactions [96,111,129,133,143,216,247,256,309], low quality of life [55,157,214,243,259,312], and addictions [220,241].
Pregnancy was another area impacted by COVID-19, especially when it concerned depression, due to its nature as a special, but also critical, moment in womens' lives [267]. In particular, WHO reported that about 10% of pregnant women experience a mental disorder, primarily depression [267], whose likelihood has increased during the COVID-19 pandemic [266,348,349]. Furthermore, for both pregnant women and their husbands, fear of COVID-19 was significantly associated with their depression level [191].
As for the COVID-19 pandemic effects on medical staff, there is some agreement between scholars. Some works highlighted that medical staff particularly suffered from the COVID-19 pandemic in terms of depression symptoms, due also to the increased workrelated risks and workload [4,8,220,222,254]. In particular, medical staff members were more likely to have an impairment of their attention, cognitive functioning, and clinical decision-making [220]. Some others found that healthcare workers were at risk to develop depression [10,213,217,219,220,231,232,235,242,254,262,268,270,350]. However, other papers found the contrary [221,260], thus suggesting that the effect of the pandemic on the depression of health workers can be mediated by factors such as: longer average working time, more time in contact with COVID-19 patients, spending more time thinking about COVID-19, and spending more time searching for coronavirus information [217,219,270]. Some protective factors individuated specifically for healthcare workers were: maintaining contacts through social networks [265], individual resilience [281], distress tolerance [281], social support [65], and having a meaning in life [312].
Depression levels during the pandemic were associated with age, gender, social condition, culture and psychological variables. The results are shown below.
Social Condition: An association between sociodemographic variables and depression was captured: lower levels of education, unemployment, lower income, living in urban areas, living in crowded areas where it is impossible to maintain social distance, not having a child, having an acquaintance infected with COVID-19 have been associated with higher levels of depression [6,8,67,185,187,226,233,245,247,248,253,264,347]. Remote working was associated with lower depressive symptoms [245], while being a student seemed to be significantly associated with higher levels of depression [4,8,186,254,265,310].
Culture: Some differences related to culture were found: during the COVID-19 pandemic, Chinese, Asian Americans, and Israeli Arabs were at low risk of present depressive symptoms, compared to Spanish, White Americans, and Israeli Jewish [7,24,355]. According to Gobbi and colleagues [326], Turkish had the lowest level of depression, compared to Canadians, Pakistanians, and Americans [326].
Comorbidity: Anxiety [38,96,223,345], stress [214,312], sleep difficulties [223,271], history of mental health issues and chronic illness [220,221,255,259,262,268,310,347,356] were consistent predictors of higher depression during COVID-19 pandemic. These results also are in line with pre-COVID-19 literature [353,354]. Table 16 shows information about the papers analyzed for the study of Depression. The COVID-19 pandemic, as well as previous epidemics (such as SARS, H1N1, Ebola virus), have caused other psychological consequences with respect to those considered in the previous paragraphs, both on individuals affected by these diseases, as well as on the non-infected ones [3,5,8,9]. In particular, four constructs about Mental Health and Quality of Life domains will be examined below due to their connection with the COVID-19 outbreak.
Wellbeing: Living under the threat of the pandemic and its consequences represented a significant challenge to wellbeing [329,350,357]: indeed, the first wave of the COVID-19 pandemic was linked to worsening in wellbeing and mental health [9,329,358]. The sudden outbreak of COVID-19 and the preventive measures had a strong impact reducing the quality of life of the population [5,93]: forcing a drastic change in habits and routines [359], reducing social contact [329], and restricting freedom of movement as a consequence of social isolation [5]. Both the sudden outbreak of a new and unknown virus and the measures adopted to decrease its spread have had a strong impact on the mental health and the psychological well-being of the population [5].
Psychological Distress: Variables positively associated with psychological wellbeing were negatively associated with psychological distress [360]. APA defined psychological distress as a set of painful mental and physical symptoms that are associated with normal fluctuations of mood in most people [361]. Furthermore, Arvids Dotter and colleagues [362] defined psychological distress as a state of emotional suffering associated with stressors and demands that are difficult to cope with in daily life. When facing something new or unknown, such as the COVID-19 virus, a lack of effective treatment can lead to psychological distress in health care professionals as well as in patients [362]. The risk of getting infected, the lockdown scenario, and the consequent changes in habits may contribute to feelings of loneliness (connected to social isolation) and psychological distress [5,359,363].
Risk factors associated with greater distress were: not having an adequate supply (of food or goods of first need) [364], quarantine [364,365], low level of health perception [364], risk control [364], risk perception [364], low social support (family) [363], negative coping styles [75], delay in returning to work and school [365], negative thoughts [366], being close to potential risk groups [9], and work environment [3]. In the pandemic, healthcare workers are at high risk of psychological distress [357]: they were worried about overtime work, the stigma of the illness, and the health of their families and themselves [279]. While, protective factors associated with distress were: taking personal prevention/protection and clothing disinfection measures, clear communication of directives, and precautionary measures [364].
Fear of COVID-19: Fear is a negative emotion accompanied by excessive levels of emotive avoidance concerning particular stimuli, and it is an adaptive danger response [133,178,367]. It is associated with clinical phobias [178], social anxiety [178], risk perception [367], health anxiety [367], bad psychological and physical health [133], use of social media [367], high neuroticism and worries [366]. However, fear to some extent can be helpful for people in terms of leading them to comply in protective behaviours against COVID-19 [107,133,178].
In particular, it is also necessary to define the fear of COVID-19, that is based on four basic pillars: fear of the body, significant others, uncertainty, and action/inaction [9,368]. Especially the uncertainty led to changes in habits that are associated with decreased wellbeing and increased psychological distress [9,178].
Sleep: Finally, sleep is an indispensable physiological process in maintaining physical health [369] and sleep quality is a key indicator of health [70]. The stressful situations caused by the COVID-19 pandemic appeared to enhance symptoms such as sleep suppression, increased wakefulness, insomnia, difficulty falling asleep, maintaining sleep, waking up early, daytime sleepiness, nightmares and daytime dysfunction, and other sleep-related disorders [69,70,188,273,283,369]. On the other side, social support appeared to reduce stress and consequently improve sleep quality, and also enhance wellbeing [70].

Measures
Wellbeing: The validated questionnaires used to measure wellbeing are reported in Table 17. Table 17. Validated tools to measure "Wellbeing". In the table are reported the psychological tools adopted by the studies taken into account, their internal consistency (reliability), and their frequency.

Psychological Tool α Fr
Fear of the Coronavirus Questionnaire (FCQ) [367] 0.77 1 The Fear of COVID-19 Scale (FCV-19S) [170] 0.82 6 COVID-19 Fear Inventory (CFI) [198] 0.82 1 The numeric rating scale (NRS) [389] no 1 Different research used ad hoc questionnaires to analyze fear [37,107,133,212,277,390]. Sleep: The already validated questionnaires used to measure sleep are reported in Table 20. Table 20. Validated tools to measure "Sleep". In the table are reported the psychological tools adopted by the studies taken into account, their internal consistency (reliability), and their frequency.

Results for Other Consequences of COVID-19 on Mental Health
The influence of COVID-19 on the levels of wellbeing, distress, fear, and sleep appeared as mediated by different factors that are reported below.
Regarding healthcare workers, it is demonstrated that their workload had a significant negative impact on their psychological wellbeing [279,400].
Distress: Greater mental distress was evident post lockdown [8,214]. The decrease in distress during the initial phase was attributed to preventive measures (including medical support and resources to stop the spread of the virus) [304]. Among the healthcare workers, high levels of distress were found [90,397,401,402], finding also that those who believed the virus was developed intentionally in a lab reported higher levels of distress [401].
Fear: Regarding the fear of COVID-19, it was associated with psychological distress and life satisfaction [170,228,403]: this was a mediating factor between intolerance of uncertainty and wellbeing [9]. According to Mertens and colleagues [367], there are four predictors of the fear of COVID-19: health anxiety, regular media use, social media use, and risks for loved ones [367]. Nevertheless, COVID-19 fear has been shown to predict positive changes in behavior (social distancing, hand hygiene) [107,170,178,390]. Furthermore, people who had higher levels of risk perception experienced more fear, and they were more inclined to develop a mental disorder [133,228]. Finally, between healthcare workers there was also a negative correlation between fear of COVID-19 and wellbeing [279,400,403,404].
Sleep: Reporting sleep-related functional problems was significantly associated with higher distress [397]. During quarantine, sleep timing markedly changed: people went to bed and woke up later, and spent more time in bed, but, paradoxically, also reported a lower sleep quality [271]. The difficulty in falling asleep was the result of an increase of "presleep cognitions", which could probably lead to PTSD [283]. According to Di and colleagues, and Bai and colleagues [395,405], even children reported sleep difficulties during the COVID-19 pandemic [395,405]. In particular, sleep disorders were higher in COVID-19 confirmed cases [223], and those who had adversity experiences/worries [69], no exercise [65], and lower social support [65,69].
According to different studies [65,184,263], healthcare workers had the highest rate of poor sleep compared to other occupations [65,184,263]. They reported more difficulty in falling asleep [314], short sleep duration [314], and more sleep disturbance like insomnia [231,314].
Wellbeing, distress, fear and sleep levels during the pandemic were associated with age, gender, social condition, culture and comorbidity.
Age: Several studies have shown that being younger and having negative self-perceptions about ageing were associated with increased discomfort [5,75,309,319,359,363,364,406,407]. Thus, as a result, older people with positive self-perceptions of ageing seem to be more resistant during the COVID-19 outbreak [8,86,363,397]. In contrast with these findings, only Zhang and colleagues [365] argued that age was positively associated with psychological distress [365]. Nevertheless, an effect of the quarantine was found even on young people: children and adolescents in quarantine suffered greater psychological distress than children and adolescents not in quarantine [166]. Sleep disorders were more frequent in younger people [256,288,408]. In particular, as far as COVID-19 hospitalized patients are concerned, sleep disorders are greater in people aged 50 and over [223].
Gender: Several studies showed that being female was associated with higher levels of distress, and lower levels of psychological wellbeing [5,86,183,233,239,309,319,363,364,397,406,407,409,410]. Finally, fear of COVID-19 was more severe in females than in males [411]. Most of the papers found the prevalence of sleep disorders as insomnia [225,408] or poor sleep quality was higher among women [256]. Only Zhpu and colleagues [263] found conflicting results: in their paper, the sleep quality of men was worse than that of women [263].
Social Condition: People who were unemployed [309,407,409] or who had just lost their job reported higher psychological distress levels [406]. As for the workers, faculty, post-doctoral researchers and students showed lower levels of wellbeing than staff members [233,345]. Another significant association was found with marital status: those who were married had higher levels of wellbeing than those who were divorced because they had more social contacts and social support [318]. A relationship emerged between job loss, being single, and sleep disorders [69,256]. In particular, unemployed mothers or mothers who continued to work outside were more likely to suffer from sleep disorders than those who continued working at home or stopped working during lockdown [405].
Culture: Only one paper investigated cultural differences. According to Kimhi and colleagues [355], Arab respondents expressed a significantly higher level of COVID-19 distress compared with Jewish ones, who, on the contrary, reported higher levels of wellbeing and resilience [355].

Discussion
This review aimed to explore the impact of the first wave of COVID-19 on people, analyzing different psychological and psychosocial dimensions. To identify the domains impacted by COVID-19 we relied on previous pandemic literature (e.g., Ebola, SARS, MERS, Novel influenza A, Equine influenza), and chose to reanalyze them in the current one. The analysis of the results revealed that the dimensions most impacted by COVID-19 among psychosocial variables were: beliefs about COVID-19, coping strategies, risk perception, social support, and compliance and social distancing.
In particular, regarding the three fundamental moderators about beliefs and media persuasion (attitudes, knowledge, and finding news on social networks) the analysis of works showed that, although some attitudes were optimistic (e.g., the probability of being infected was perceived as low), most participants took precautionary measures to prevent infection [34]. On the contrary, higher levels of negative thoughts (e.g., fatalism toward the pandemic) were associated with lower behavioral intentions to comply with protective measures [36]. Furthermore, accurate knowledge about COVID-19 predicted more information-seeking behaviour, the ability to discern between true and false information, compliance with preventive measures, and showed lower panic reactions, a lower level of anxiety, and greater risk perception [25,41,126]. The major sources people used to seek information during the pandemic were TV and social media, but these also led to an increase in disinformation and a spread of fake news and conspiracy theories [16,17,43]. Regarding conspiracy theories about COVID-19, some studies showed that subjects who believed in them complied less with the suggested protective behaviours and were less likely to get vaccinated [18,51,52]. On the contrary, those whose core beliefs (beliefs that guide individuals in their identity) were less influenced by the pandemic reported to engage more in social isolation measures [38].
Beliefs about COVID-19, its transmission, and its protective measures, demonstrated to strongly influence compliance with them. In particular, low compliance was associated with belief in conspiracy theories, impulsivity, and self-centered behaviour [48,49]; instead, higher compliance with protective measures was associated with fear of COVID-19, trust in government and science, and higher risk perception [134,154,169,179].
The risk perception has shown a double effect: on the one hand, a higher risk perception induces higher levels of compliance, for example, in terms of compliance with social distancing [56]. On the other hand, however, it can lead to avoidant behaviors, such as being reluctant to seek medical assistance for fear of transmission, which can damage both the health of the individual and make the management of the pandemic more difficult, probably due to the sense of loss of control that is notoriously associated with high levels of risk perception [100,185].
Quarantine, and the COVID-19 pandemic in general, also had negative social consequences. For example, many social support networks have been interrupted: indeed, social distancing led to boredom, loneliness, social isolation fatigue, anxiety, and depression [54,135,159]. Nevertheless, social support proved to be crucial and had a positive impact on coping with the COVID-19 pandemic [56,59,66]. The results showed that positive coping strategies were correlated with less distress, fear, and general vulnerability, and higher wellbeing. In contrast, negative coping strategies (e.g., substance use, behavioral disengagement) were related to higher stress, distress, fear, and anger [77,79,88].
In addition, psychological dimensions regarding some areas of mental health, specifically anxiety, stress, depression, wellbeing, and sleep, were impacted due to the pandemic.
Restrictive measures had, in general, a protective effect on anxiety, whereas being more in contact with the virus resulted in higher levels of it. In particular, anxiety was negatively related to protective measures from COVID-19 [23,73,168], whereas it related positively to testing positive for COVID-19, being in an environment exposed to COVID-19 [58,110,219], knowing people who were COVID-19 positive [201,221,222], and having more knowledge about COVID-19 [16,23,41].
The COVID-19 pandemic was also associated with higher levels of depression, both in people with a history of psychiatric disorders and in others [78,326]. These results seemed to be due to quarantine and social isolation, but also to the constant exposure to information about COVID-19 [187,223,251].
Stress appeared to be positively related to the COVID-19 pandemic and the subsequent lockdown period [7,78,307]. This effect is buffered by some protective factors, such as lower exposure to COVID-19 [233,273]and some personality traits, such as emotional stability and conscientiousness [74].
The research has highlighted some risk and protection factors of wellbeing during the pandemic. Quarantine, living in areas with high virus prevalence, overexposure to COVID-19 information, and conspiracy theories seem to decrease wellbeing; while exercise, positive coping strategies, and greater social support seem to promote it [8,399].
The pandemic also impacted the distress experienced by people, particularly of those who were already physically and/or mentally ill. Indeed, poor sleep quality was positively correlated with stressful situations caused by the COVID-19 pandemic [69,273,369].
Overall, the COVID-19 experience may be useful to derive some evidence-based insights to be applied in case of future similar emergencies. Concerning compliance, promoting a correct risk perception in the population by disseminating correct information [17,19,20,39,46,169], and suggesting effective (and positive) coping strategies [71,77,87,91,93,94], would be helpful in increasing the degree of compliance with governmental measures [39,48,76,95,102,104,105,120,123,127,134,137,139,142,148,152,169,178]. Nonetheless, compliance is also affected by the perception of the effectiveness of such restrictions. For this reason, a better media campaign, focused not on fear but on efficiency (and self-efficacy), would be ideal, in the event that an extreme situation, such as the COVID-19 pandemic, should recur [21,24,40,41,46,49,169].
As highlighted by the literature, different management of the emergency would have also led to better psychosocial and psychological outcomes. In this regard, social support appeared to ease emergency management [55,66,67,[69][70][71]. Greater social support was also useful in reducing the levels of anxiety, depression, stress, that ultimately contributed to people's compliance with the rules, fear of contagion, and management of the emergency (both collectively and individually) [55,67,70,71]. Given the widespread increase in psychological/psychiatric symptoms (anxiety, depression, stress, insomnia, and psychological distress) [4,58,64,96,225,233,243,271,319,347], countries all over the world, especially those most affected by the virus, should envisage in such situations a prompter professional support to citizens, so to prevent the emerging or worsening of symptoms.
Finally, one of the factors identified in the scientific literature as key to countering the pandemic was resilience. Resilience resulted in stress [259,311], anxiety [24,57,133], and depression [157] protective factors, and has a positive relationship with wellbeing [329]. Resilience is fundamental in enabling people to change their behaviour in response to stressful events, like the COVID-19 pandemic, which in this specific case may prevent someone from getting sick or dying. For this reason, resilience appears to promote readiness to change, which is one of the factors that enable communities to respond adequately to emergencies such as a pandemic [12][13][14].
As described above, the pandemic affected several psychological dimensions. However, its effect appeared to be conditioned by a few factors that allowed us to qualitatively describe the psychological and socio-demographic profile of the most resilient people. The factors that more frequently had a significant influence on the previously analyzed variables are: age, gender, culture, social condition, healthcare workers and workload.
As for age, younger people appeared to be less resilient: they were more affected in terms of both psychosocial variables and mental health. Young people showed greater compliance with preventive measures, probably due to their greater risk perception and knowledge of the virus. Despite their major levels of compliance, young people suffered more from the effects of quarantine, implemented negative coping strategies more often, and suffered more from psychological distress and, in general, mental health problems (i.e., anxiety, depression, stress) [24,40,73,74,143,154,157,166,347].
Similarly, women were most affected by the pandemic: they tended to comply more with the rules because they were more worried and perceived greater risks, so they mainly used emotionally focused coping strategies. Again, despite showing higher compliance levels, women were more susceptible to anxiety, depression, stress, sleep disorders, and distress than men [89,114,139,187,223,363,408]. Furthermore, post-partum depression in-creased during the pandemic [266,348,349]. In light of this, young women appear to be the least resilient, especially under certain conditions such as postpartum.
An effect of culture was particularly evident on beliefs: collectivist societies seemed to have more accurate beliefs about COVID-19 than individualist societies [47,49]. However, the levels of risk perception, as well as people's mental health, apart from possible cultural factors, appeared to be affected by the levels of contagion around the world. So, it was not possible to distinguish between the two causes which one influences more the results [78,127].
Lower levels of education were associated with more fear of dying by COVID-19, perception of susceptibility to the infection and worse overall knowledge about the pandemic [47], more anxiety [247], stress [258] and depression [347].
Lower income and unemployment were associated with higher levels of anxiety [247], stress [56], depression [347], higher levels of distress [406] and more sleep disorders [69,256]. The results about compliance and social distancing were conflicting regarding income [40,101,141,149].
Finally, healthcare workers experienced an increase in workload that led to several consequences, including higher risk perception [127], higher levels of anxiety [184], stress [288], depression [222], less wellbeing [232], worse sleep quality [184], and higher risk of psychological distress [357]. Healthcare workers implemented coping strategies like religious strategies, acceptance, planning, physical activity, virtual support groups, talk therapy, and positive framing [8,87,90]. Of these factors, some (e.g., age, gender) are known to be relevant to mental health even before the pandemic; nevertheless, the papers we analyzed did not distinguish the effects of these variables before and after the pandemic.
In conclusion, the aim of the paper was to research how the COVID-19 pandemic impacted the psychological health of the global population during the first wave. In particular, we investigated which psychosocial and psychological variables were most affected, delineating a first and preliminary picture of symptoms related to COVID-19 that could be called "psychological COVID-19 syndrome". This syndrome appeared to be characterized by an increase in stress, depression, anxiety, sleep disturbance, and distress related symptoms. Healthcare workers were the most affected by the consequences of the COVID-19 pandemic, as they found themselves on the front lines facing the virus and experienced a sudden increase in workload. In addition to healthcare workers, the results showed that people who proved less resilient were young women, with low income and low education, particularly if they were in post-partum condition. In light of this, it would be hopeful to implement prevention and aid projects for these individuals, particularly affected by the pandemic.
The number of studies about the psychological effects of the COVID-19 pandemic is increasing. However, the literature available until June 2020 was still in the early stages of maturity. Therefore, thanks to the articles published since June 2020, the "psychological COVID-19 syndrome", hypothesized in this review through the first wave studies, could be modified or expanded. Future research should investigate the second and third waves of the pandemic so that comparisons can be made with the present research.

Data Availability Statement:
The data presented in this study are available on request from the corresponding author.

Conflicts of Interest:
The authors declare no conflict of interest.      The general population with a history of visits to Wuhan, those with a history of epidemics, ant those who perceived more severe impacts of the COVID-19 epidemic on their lives, emotional control, and epidemic-related dreams had a higher level of psychological distress than those with none or little of these experiences. During the C-19 outbreak, the degree of concern about media reports influenced the general population's level of psychological distress and coping style. Media reports could influence the perception of the disease and the preventive measures implemented.
[139] Norway 8676 Risk Perception Increased media exposure, perception of measures as effective, and of the epidemic as a serious endeavor lead to positive predictions for health protection behavior.
[25] Perù 225 Risk Perception Knowledge is highly correlated with education, occupation, and age.
[221] Spain 3550 Anxiety, A substantial portion of the sample analyzed Depression, exhibited symptoms of depression, anxiety, Stress stress, and PTSD as measured on validated scales. In addition, respondents showed high levels of concern for their own health and that of relatives such as their parents, as well as for the social and economic situation resulting from the COVID-19 crisis.
[20] USA 955 Beliefs/ The effectiveness of the fear intervention was less Media Persuasion dependent on the strength of the emotional response than the prosocial intervention. In contrast, the prosocial message was more effective in increasing the willingness to self-isolate if it produced a strong, positive, emotional response. Both fearful and prosocial messages were equally effective in stimulating engagement in protective behavior.
[91] China 97 Coping Mindfulness reduced daily anxiety. The sleep duration of participants in this condition was less affected by increased infections in the community than participants in the control condition.
[22] MTurk 210 Beliefs/ Social distancing is significantly influenced by situational awareness. Media Persuasion Information sources, formal and informal were found to be significantly related to perceived understanding.
[248] England 2025 Anxiety, Higher levels of anxiety, depression, and trauma symptoms Depression, were reported, but not dramatically so. Anxiety Stress and depression symptoms were predicted by low income, loss of income, and preexisting health conditions. C-19-specific anxiety was greater in older participants.
[109] Vietnam 391 Risk Perception 11% of respondents did not actively search for information on C-19, while over 80% admitted to searching at least 2 times per day. A higher rate of anxiety, depression, hazardous Depression, and harmful alcohol use, and lower mental well-being Other Consequences in the Chinese population following the C-19 pandemic. The findings also revealed that young people are in a more vulnerable position in terms of mental health conditions and alcohol use. Young people are at higher risk for stress (despite lower mortality) as they take information from social media.
[58] China 7143 Anxiety 0.9% of respondents had severe anxiety, 2.7% moderate anxiety, and 21.3% mild anxiety. Living in urban areas, family income stability, and living with parents were protective factors against anxiety. Having relatives or acquaintances infected with COVID-19 was a risk factor for increased anxiety. Economic effects and effects on daily life, as well as delays in academic activities, were positively associated with anxiety symptoms, whereas social support was negatively correlated with anxiety level.
[109] Vietnam 391 Risk Perception 11% of respondents did not actively search for information on COVID-19, while over 80% admitted to searching at least 2 times per day.
[359] Spain 584 Other consequences Participants reported an important increase in negative affect and an important decrease in positive affect during the lockdown period, compared to before the lockdown.
[24] China 10,905 Beliefs/Media Persuasion In general, 74.1% of participants acknowledged the effectiveness of overall control measures and it was negatively correlated with regional number of existing cases.
[147] China 1920 Compliance All studies together confirms that intentions to wear a face covering are higher in the priming reason condition compared to the priming emotion condition.
[44] USA 1034 Other Consequences Self-reported emotions showed that women were more worried, anxious, scared, and sad than men, and these results were supported by language differences. In addition, models showed that men wrote more frequently about concerns related to their health than women.
[164] China 1011 Anxiety The prevalence of moderate to severe anxiety was 4-5 times its normal level in urban China. The majority engaged in all six behaviors. Confusion about the reliability of information significantly fueled public anxiety levels.
[120] Vietnam 345 Risk Perception Those who use medical masks have a higher perception of risk than other people. This implies that people chose to wear a medical mask before the pandemic broke out perceive a higher risk than their counterpart. People tend to perceive greater risk as they age.
[47] China 1075 Beliefs/ The majority of respondents appear to take the risk of C-19 Media Persuasion (on themselves, their community, and their livelihood) very seriously and are aware of ways to reduce risk. Education was an important demographic determinant, and the impact of age is likely associated with both education and life experience. Women and those with more than 10 years of employment, Depression, concomitant chronic illnesses, history of mental disorders, Stress and confirmed or suspected family members or relatives are prone to stress, depression, and anxiety among nurses during the COVID-19 pandemic.
[148] MTurk 1439 Compliance Greater concern and weaker endorsement of unfounded C-19 beliefs leads to more responsible behavior. Overall levels of anxiety and adoption of positive behaviors Italy were strongly influenced by the sufficiency of information in all three countries, demonstrating that population-level risk perception, self-efficacy, and response to an outbreak can be intensified or attenuated by the quantity and quality of information provided.
[126] Canada, 1975 Risk Perception Cognitive sophistication-that is, the quality of one's reasoning UK, USA was associated with lower misperceptions in all three countries. In fact, in both the United States and the United Kingdom, cognitive sophistication was a stronger predictor of resistance to misperceptions than political ideology.
[127] Italy 353 Risk Perception Medical personnel in Northern Italy were more stressed and anxious than those in Central and Southern Italy. HCWs reported higher risk perception, level of concern and knowledge regarding C-19 infection than the general population.
[227] USA 303 Anxiety, 69.0% of the sample reported moderate to severe levels of anxiety. Other Consequences Changing behavioral factors were better predictors of anxiety than psychological, situational, or informational factors, but all were significant.
[186] China 1210 Anxiety, 53.8% of respondents rated the psychological impact Depression, of the outbreak as moderate to severe; Stress 16.5% reported moderate to severe depressive symptoms; 28.8% reported moderate to severe anxiety symptoms; and 8.1% reported moderate to severe stress levels.
[413] China 205 Depression A higher prevalence of depression was found primarily in patients who had C-19 infection.  Being female, younger, having negative self-perceptions about ageing, more exposure to C-19 news, more contact with relatives other than those residing in the home, less positive emotions, less perceived self-efficacy, lower sleep quality, less positive emotions, and higher loneliness were associated with greater distress.
[159] MTurk // Compliance Confinement measures are associated with aversive experiences including boredom, so adherence is likely to require self-control. Compared with nonclinical staff, frontline medical personnel with close contact with infected patients showed higher scores on the Fear, HAMA, and HAMD scales, and were 1.4 times more likely to experience fear and 2 times more likely to experience anxiety and depression.
[216] China 1738 Anxiety, Statistically significant longitudinal reduction Depression, in mean IES-R scores after 4 weeks. Moderate Stress to severe stress, anxiety, and depression were observed during the initial assessment. Hand hygiene, mask use, and trust in physicians reduced psychological impact.
[410] Denmark 2458 Other Consequences The psychological well-being of the general Danish population is negatively affected by the COVID-19 pandemic. Females were more affected than males by the C-19 pandemic, in agreement with findings in other countries, reporting lower levels of well-being than their male counterparts.
[201] USA 775 Anxiety High CAS scores were associated with C-19 diagnosis. The study showed a higher prevalence of symptoms in females. Finally, the study demonstrated the relationship between self-reported sleep conditions and the prevalence of PTSD, showing that participants with worse sleep quality had a higher prevalence of PTSD.
[5] Italy 1639 Stress Of 1639 respondents equally distributed in the Italian territory, Other Consequences 5.1% reported PTSD symptomatology, and 48.2% evidenced lower psychological well-being linked to COVID-19 diffusion.
[272] China 307 Anxiety, The prevalence of anxiety, depression symptoms Depression, were 18.6% and 13.4%, respectively. Other Consequences PSQI scores were significant positively associate with SAS scores and SDS scores (p < 0.05).
[327] Italy 250 Anxiety, Analysis of the data showed satisfactory psychometric characteristics Depression, and confirmed the scale's unidimensional properties. Other Consequences Construct validity for the FCV-19S was supported by significant and positive correlations with the HADS and SMSP-A.
[240] MTurk 219 Anxiety, During the initial C-19 impacted academic term (Winter 2020), Depression, individuals were more sedentary and reported increased anxiety and depression symptoms, relative to the previous academic terms and subsequent academic breaks.
[347] Mexico 6023 Depression, Regarding indicators of psychological distress Stress mean values for severities of depression and anxiety reached the respective cutoff scores for mild degrees, and the mean score of the IES-6 was borderline.
[412] Turkey 126 Other Consequences The impact of the health anxiety on wellbeing levels among mothers with autistic children is stronger than it is among mothers with normotypic children. The results showed that prevalence of anxiety, Depression, depression and PTSD was 14.4, 29.7, and 5.6%, respectively. Stress There was a significantly positive correlation between anxiety and depression/ PTSD.
[59] // // Anxiety, Stress, A systematic review that investigate the impact of the Depression pandemic on mental health and the related implications.
[241] Mexico 561 Anxiety, In the initial phase of the pandemic the prevalence for anxiety Depression and depression was 50% and 27.6%, but during the lockdown was incremented by 51% and 86% respectively.
[59] // // Anxiety, Stress, A systematic review that investigate the impact of the Depression pandemic on mental health and the related implications.
[8] Pakistan 1134 Anxiety, The frequency of anxiety and depression was 34% and 45%. Depression, The main sources of distress were related to adverse effects of Other Consequences, ongoing pandemic on daily life. The main coping strategies Coping adopted were religious/spiritual coping and acceptance.   Depression, There was a significant relation between Stress, gender and variables of depression, anxiety, and stress. Anxiety There was also an inverse relationship between stress and variables of educational level and age.
[51] France 805 Beliefs/ Conspiracy beliefs positively predicted a pro-chloroquine Media Persuasion attitude. The same relations were found with vaccine attitudes, intention to be vaccinated, and pro-chloroquine attitudes.
[38] USA 408 Anxiety Adhering to social isolation policies predicted lower levels of C-19 Anxiety. This effect was largely mediated by conservation of core beliefs and ability to make meaning of the pandemic.
[223] China 66 Anxiety, Depression The incidences of anxiety, depression, and sleep disorders Depression in the suspected case group were 18.2%, 18.2%, and 39.4%. The anxiety, depression and sleep disorder scores were significantly positively correlated (p < 0.05).
[183] Italy 944 Anxiety, 46% of participants presented moderate to extremely severe Depression, symptoms of depression, 40% presented moderate to extremely Stress, severe symptoms of stress, and 30% presented Other Consequences moderate to extremely severe symptoms of anxiety. People well-endowed with transcendence strengths (e.g., hope, zest, gratitude) scored higher for general mental health, lower for psychological distress (fewer symptoms of depression, anxiety and stress), and higher for self-efficacy in coping with the lockdown situation.   [234] United Arab 1485 Anxiety, Almost half of students reported anxiety levels from mild Emirates Other Consequences to severe, with females reporting higher anxiety scores, and medical students reporting lower anxiety than dental students.
[75] China 584 Coping, 40.4% of young sample were prone to psychological Stress, problems, as they reported PTSD symptoms and Other Consequences negative coping strategies. Coping, There was a significant inverse relationship between Other Consequences severe psychological distress and motivation for distance. The most common coping strategy among students was spending more time on social media.
[261] USA 898 Anxiety Loneliness, C-19 specific worries, and distress tolerance were significantly associated with anxiety.  86% patients with RD were unwilling to go to the Depression, hospital, while 22% discontinued their medications. Stress The frequency of anxiety (20%), depression (43%) and stress (28%) among patients with RD were found to be comparable to that among the teachers/academic staff, whereas significantly less than that among HCWs.
[70] China 180 Anxiety, Stress, Levels of social support for medical staff were Social Support, significantly associated with self-efficacy and sleep quality Other Consequences and negatively associated with the degree of anxiety and stress. Anxiety was significantly associated with stress, which negatively impacted self-efficacy and sleep quality. Anxiety, stress, and self-efficacy were mediating variables associated with social support and sleep quality.
[99] South Korea 973 Beliefs/ Respondents' perceived risk of COVID-19 infection. Media Persuasion, The average perceived severity score was higher than Compliance, perceived susceptibility. Precautionary behaviors were Risk Perception associated with perceived risk and efficacy. [315] Spain 3109 Stress Of the 1671 physicians who completed the survey, the highest psychosocial impact was perceived in Respiratory medicine and Geriatrics. Higher distress levels were found in the areas with the highest incidence of COVID-19.
[187] Italy 2766 Anxiety, There is an associations between sociodemographic variables, Depression, depression, anxiety, and stress levels during the C-19 outbreak. Stress Higher levels of negative affect and detachment were associated with higher levels of depression and anxiety. Conspiracy was positively correlated with the adoption Risk Perception of non-normative prevention behaviours, in contrast, no association was observed with the adoption of normative prevention behaviours. Furthermore, conspiracy was associated with a greater perception of risk of contamination of the French population, personal contamination, and risk of death. Individuals showed biases in their risk perception concerning overconfidence and the underestimation of exponential growth of infection cases in the early phase of the pandemic. Risk perceptions increased with perceived dread and tended to increase with perceived control over infection, the evaluation of scientific and own knowledge about the pandemic.
[314] China 371 Stress, 1 month after the outbreak, the prevalence of PTSSs was Other Consequences 3.8% in HCWs. HCWs with higher exposure level also rated more hyperarousal symptoms. In summary, targeted interventions on sleep contribute to the mental recovery during the outbreak of COVID-19. The shows that worries about the individual, social, and Other Consequences economic consequences of the crisis, strongly boost stress. The infection rate in the zone of residence also contributes to stress. Positive thinking and perceived support mitigate worries and stress. [123] USA 100 Risk Perception Participants rated both the USA and European governments as somewhat unprepared for future outbreaks, they were less concerned with personally being infected but they perceived the disease as quite severe, they were very likely to get vaccinated. [154] USA 302 Compliance Perceived norms were lower than individuals' own beliefs.      [230] USA 474 Anxiety Those in threat condition reported a higher likelihood that the prevalence of C-19 would increase in the future and also reported greater harm to the US from C-19.
[351] China 5115 Depression Participants who reported greater flow also reported more positive emotion, less severe depressive symptoms, less loneliness, and more healthy behaviors. Interactions with quarantine length were more consistent.
[96] China 1346 Anxiety, Significant correlations were found between anxiety Risk Perception, and perceived risk, positive affect and negative affect; Depression depression correlated with perceived risk, positive affect, negative affect and anxiety symptoms.
[399] Brazil 592 Other Consequences Wellbeing related to physical activity during quarantine was linked to an established routine of physical activity before the social isolation period.
[79] China 117 Compliance Psychological distress during the pandemic Risk Perception was associated with greater C-19-related catastrophizing, increased general health anxiety, greater support-seeking coping, but less use of problem-focused coping.
[185] Turkey 318 Anxiety, Female gender, living in urban areas and previous psychiatric Depression illness were found as risk factors for anxiety and depression.
[271] Italy 1310 Anxiety, During lockdown, sleep timing changed (people going to Depression, bed and waking up later), but also reporting a lower Stress, sleep quality, especially for those with a higher Other Consequences level of depression, anxiety and stress symptomatology.
[78] Italy 1163 Coping, Stress, The perceived impact on health was significantly higher Depression, in HCWs and in people living in northern Italy. A significant Risk Perception indirect effect of problem-oriented coping was found.
[184] China 7236 Anxiety, The prevalence of anxiety symptoms, depressive symptoms, Depression, and poor sleep quality were 35.1%, 20.1%, Other Consequences and 18.2%, respectively. Other Consequences Females, young people, and those with higher fatigue and anxiety severity were more likely to experience insomnia.
[54] China 182 Anxiety, Chinese overseas students experienced a Social Support higher level of anxiety than the Chinese population.
[356] USA 374 Depression Factors associated with depression included: degree of C-19 interference with the treatment of cancer, and concern that patients will not receive the level of care needed.
[321] India 100 Stress, Female college students are severely affected by PTSD, Depression and present a correlation between depression and avoidance.
[390] Japan 1148 Other Consequences The number of workplace measures correlated positively with respondents' fear and worry, negatively with distress.
[89] USA 1015 Coping, The most common stressor is reading about the severity of Stress, C-19, uncertainty about length of quarantine and social Compliance distancing requirements. Most common coping strategies: distraction, active coping, and seeking emotional social support.
[95] Qatar 405 Compliance, 87.3% of participants reported that they stay at home, Risk Perception 60.3% said that they maintain an adequate distance, and 73.5% believed that COVID-19 is a dangerous disease.
[16] USA 464 Anxiety, Compliance, Most of the people received information through TV, social Risk Perception, media, family and friends. Only 35.1% stated that they were Beliefs/ likely to contract C-19; nearly 38% did not consider Media Persuasion C-19 serious for themselves; 47.8% had high levels of anxiety.
[245] Portugal 1280 Anxiety, Severe depression and anxiety symptoms existed in 7.6% Depression and 9.1% of the sample.
[77] USA 269 Coping, Active coping, denial, use of emotional support, humor, Other Consequences religion, and self-blame were associated with wellbeing.
[94] China 2640 Coping Behavioral coping showed the highest level, and emotional coping the lowest.
[93] Poland 353 Coping, Most used strategies for coping with the stress generated Other Consequences by C-19 are: emotional support, planning, acceptance.
[71] China 1588 Coping, Suspected cases of C-19 had high psychological distress, Other Consequences, spent more time searching for information, they rarely Social Support used any coping style to deal with the stressor, and had less social support.
[138] Norway 10,084 Compliance Social distance may lead to self-isolation, that could cause severe consequences (feeling loneliness).
[133] Turkey 204 Anxiety, Stress, Perceived risk was significantly and positively correlated Depression, with coronavirus fear, depression, stress, and anxiety, Other Consequences and negatively associated with resilience.
[87] China 534 Coping, Coping strategies, strict protective measures, knowledge of Stress prevention and transmission, social isolation, and positive self-attitude resulted in less stress.
[313] Turkey 475 Stress C-19 stress had negative correlations with meaning in life and optimism, as well as positive associations with pessimism and depressive symptoms.  Coping It was found that nurses' anxiety, fear, sadness, and anger was significantly higher than the emotional level of nursing college students.
[161] USA 1070 Compliance, Women adhere more to preventive behaviors than men. Anxiety During pandemics, policymakers may benefit from disseminating preventive health messages purposely tuned to motivate adherence by men.
[254] China 702 Depression, Risk of severe depression in rst-line Stress staff was 6.63 fold; the risk of severe panic disorder was 2.62 fold higher than non-rst line group.
[152] Bangladesh 350 Compliance Better self-control ability, higher education and good mental health emerged as factors that significantly shaped the precautionary behaviors of young adults in this study.
[317] MTurk 54,245 Stress Higher levels of stress are associated with younger age, being women, being single, staying with more children, and living in collectivist cultures.
[124] USA 2135 Risk Perception US adult residents severely underestimated their absolute and relative fatality risk.
[150] UK 2025 Compliance All three COM-B components significantly predicted good hygienic practices, with motivation having the greatest influence on behaviour. [6] USA, Canada, 2065 Anxiety, Stress, Cross-sectional findings indicated elevated anxiety Europe Depression and depressive symptoms associated with COVID-19 concern more strongly than epidemiological objective risk.
[352] China 1951 Depression Credibility of real-time updates and confidence in the epidemic control are associated with a decline in depression but an increase in happiness.
[25] South America 600 Beliefs/ Our study identified that, although people reported Media Persuasion adequate knowledge by identifying expected symptoms and coronavirus transmission process.
[180] Croatia 1854 Compliance Parents, mothers especially, represent the most concerned group, regardless of age. People with chronic health conditions also expressed greater concern and safety behaviour than healthy participants.
[249] Turkey 103 Anxiety, Anxiety, hostility, and phobic anxiety were higher Depression in participants over the age of 29 years.
[37] United Arab 2200 Beliefs/Media Persuasion, Females, those who felt public fear as justifiable, Emirates Risk Perception, worried about C-19, intended to take the vaccine, Other Consequences, and smokers were all associated with anxiety. Anxiety [403] Mexico 2860 Other Consequences There was a significantly higher level of fear in nursing and administrative personnel.
[239] China 474 Anxiety, Depression, Age had a curvilinear relationship with Other Consequences nonsomatic pain, depression, and anxiety. Female gender, pre-existing psychiatric condition, Stress and prior exposure to trauma were identified as risk factors, whereas optimism, ability to share concerns with family and friends, positive prediction about COVID-19, and daily exercise predicted fewer psychological symptoms.
[283] China 2027 Stress The results showed rapid growth in the first 4 days, Other Consequences and then decreased in the last days, both in PTSD and in sleep-related problems.