Psychological Effects of Home Confinement and Social Distancing Derived from COVID-19 in the General Population—A Systematic Review

(1) Background: Home confinement and social distancing are two of the main public health measures to curb the spread of SARS-Cov-2, which can have harmful consequences on people’s mental health. This systematic review aims to identify the best available scientific evidence on the impact that home confinement and social distancing, derived from the SARS-CoV-2 pandemic, have had on the mental health of the general population in terms of depression, stress and anxiety. (2) Methods: A systematic search was conducted on PubMed, Scopus, Web of Science and ScienceDirect between 2 January 2021 and 7 January 2021, in accordance with the recommendations of the PRISMA Declaration. The selection of studies and the evaluation of their methodological quality were performed in pairs, independently and blindly, based on predetermined eligibility criteria. (3) Results: The 26 investigations reviewed were developed in different regions and countries. Factors that are associated with poor mental health were female gender, young ages, having no income and suffering from a previous psychiatric illness. Inadequate management of the pandemic by authorities and a lack or excess of information also contributed to worse mental health. (4) Conclusions: There are groups of people more likely to suffer higher levels of anxiety, depression and stress during the restrictive measures derived from COVID-19.


Introduction
In December 2019, the SARS-CoV-2 emerged in Wuhan, China. The World Health Organization (WHO) declared the disease caused by this virus (the COVID-19) as the sixth international public health emergency and proclaimed the situation as a pandemic on the 11th of March of 2020 [1]. Since the pandemic began, many countries implemented public health measures, such as social distancing or home confinement, with the aim of minimizing the spread of this virus [2][3][4]. These interventions to protect the physical health of the population altered global patterns of behaviour producing changes in the economy, way of working, social interactions or daily life [5], which, in turn, can lead to an increase in the prevalence of health risk behaviours and psychological disorders [6][7][8][9].
Most studies that analyse the mental consequences in the general population of some previous epidemics and pandemics focus on symptoms related to the aftermath of the disease itself without taking into consideration the effects of social distancing or home confinement [10]. However, large-scale disasters have also been observed to increase the prevalence of different mental and behavioural disorders such as anxiety, depression, posttraumatic stress disorder (PTSD) or substance abuse [11][12][13][14]. We can take the Severe Acute Respiratory Syndrome (SARS) epidemic in 2002 as an example because this situation led to an increase in people with PTSD and psychological distress, and not only among people who suffered from the SARS disease but also among their relatives or health workers, symptoms that persisted for a long period of time [15]. Quarantine during the SARS outbreak was also associated with high rates of anxiety (28.9%) and depression (31.2%) [4].
The elderly and people with underlying diseases are particularly at risk for SARS-Cov-2 infection, but in terms of mental health as a result of measures to slow the spread of the virus, other factors appear to be contributing to the development of psychological symptoms during the pandemic [5][6][7][8][9]. For example, younger age has been linked to feelings of loneliness during the COVID-19 pandemic, leading to symptoms of anxiety and depression in this group [16]. In addition to economic losses, occupational deprivation and the pandemic itself, social isolation is the main cause of psychological symptoms during the COVID-19 [16]. Home confinement and social distancing during the pandemic have already been shown to be associated with adverse psychological outcomes, even in un-infected people [16,17], such as emotional disorders, depression, anxiety, stress, irritability, insomnia, PTSD, anger and emotional exhaustion [18], or risky behaviours and increased substance abuse [19]. This situation makes even more evident the need to pay attention to and strengthen the public's mental health in order to minimize as much as possible the consequences of loneliness and social isolation due to the COVID-19. Therefore, investigation on this subject is justified to provide appropriate care, focused on the prevention and treatment of mental illnesses that will arise during and after the pandemic, as well as to establish programs and policies to support the global population during the crisis.
The main objective of this study was to identify the best available scientific evidence on the impact that home confinement and social distancing, derived from the SARS-CoV-2 pandemic, have had on the mental health of the general population in terms of depression, stress and anxiety.

Materials and Methods
In accordance with the recommendations of the PRISMA Declaration [20] and following the previously established research protocol, a systematic review of the scientific literature was made between 2 January and 7 January 2021. The electronic version of the following databases was consulted: PubMed, Scopus, Web of Science and ScienceDirect.
The search began with the formulation of a clinically answerable research question in PIO format, according to the criteria established by Sackett et al. [21] (Table 1).

Population
General adult population

Intervention
Measure the effect of social distancing and home confinement resulting from the COVID-19 pandemic on mental health

Outcomes
Depression level, stress level and anxiety level

Research Question
Do the social distancing and home confinement regulations resulting from the SAR-CoV-2 pandemic have repercussions on the mental health of the general population, affecting their levels of anxiety, stress or depression?
Having asked that question, and according to it, different search strategies were designed and adapted to the particularities of each of the databases consulted. The appropriate "medical subjects headings" (MeSH), combined with boolean operators (AND/OR), together with free text terms, some of them truncated, were used in order to include all possible terminations (Table 2).
Those original research studies (1) with a cross-sectional or longitudinal descriptive type methodological design, (2) published in English, Spanish, French, Italian or Portuguese, (3) published from December 2019 onward, (4) with, at least, the summary being available, (5) that in their results evaluate the level of depression, stress and/or anxiety of the general population during the SARS-CoV-2 pandemic were selected. Clinical case reports, scientific letters or low-quality scientific records, and studies that did not answer the research question and were not related to the purpose of the review or those that analysed specific sub-groups of the population (children, youth, university students, health professionals, the elderly, people with specific diseases or pregnant women) were excluded. Table 2. Search strategy used, adapted to each of the databases.

Web of Science
As a secondary strategy, a manual reverse search (also known as "snowball searching") was performed in order to identify possible relevant studies that were not previously taken into account. Sources of grey literature and bibliographic references cited in the selected studies were reviewed.
The selection of studies and the evaluation of their methodological quality were performed in pairs, independently and blindly, solving possible discrepancies by consensus and, if not, through the participation of a third evaluator. To ensure the homogeneity of all researchers in the collection of information, a standardized data extraction form was designed, including the following items for each of the selected articles: title and lead author, country and year of publication, type of study and objective, place and period of publication, sample size and characteristics, the definition of the analysed variables and instruments used, a brief summary of the obtained results and conclusions, along with the results of the evaluation of their scientific and technical quality. The "critical appraisal tools" of the Joanna Briggs Institute of the University of Adelaide (Australia) [22], suitable for the design of each study [23,24], were used for the evaluation of the methodological quality and the risk of bias. As a cut-off point for accepting the inclusion of the study in the systematic review, a minimum value of 6 out of 8 was considered for cross-sectional descriptive studies and 6 out of 9 for longitudinal studies. A pilot test was conducted in which each reviewer had to evaluate 3 articles, posteriorly analysing the concordance between their ratings.

Results
Of the 608 studies initially identified, 26 were selected for systematic review after a critical reading of the full text ( Figure 1).

Results
Of the 608 studies initially identified, 26 were selected for systematic review after a critical reading of the full text ( Figure 1).

Figure 1. Study selection flowchart.
The main characteristics and results obtained in the selected studies are summarized in Table 3. The main characteristics and results obtained in the selected studies are summarized in Table 3.

Description of the Characteristics of the Studies
The number of participants in the studies ranged between 343 and 15,308, over 18 years of age. A total of 72,056 subjects, with the female gender predominating in most of the selected studies. All the articles reviewed analysed the mental health of the adult population as a consequence of restrictive measures to stop the spread of the virus, such as home confinement and physical distancing, with the main emphasis on stress, anxiety, depression and PTSD. Sleep quality and substance abuse were not assessed in this review. Most of the studies (n = 24) were cross-sectional, and the other two were longitudinal designs. In terms of geographical distribution, the studies were performed in different regions and countries with very different health systems: China (n = 6), Spain (n = 3), Germany (n = 2), United Kingdom (n = 2), Saudi Arabia (n = 1), Brazil (n = 1), India (n = 1), South Korea (n = 1), Pakistan (n = 1), Jordan (n = 1), Italy (n = 1), Vietnam (n = 1), Turkey (n = 1), Bangladesh (n = 1) and the US (n = 1), noting that two of them were performed in several countries. In total, 31.1% exceeded the cut-off score for a depression diagnosis, 21.2% for anxiety disorder and 29.4% for health anxiety. Women reported more anxiety and depression than men. Being young, low educational level, unemployment, current or previous psychiatric treatment, belonging to a risk group, anguish related to the restriction of social contacts, and a greater perception of change predicted depression and anxiety (p < 0.001). Living alone also contributed to increased anxiety.

8/8
Chen et al. [29], 2021 Design: Quantitative cross-sectional Objective: To compare the anxiety levels of confined people with those who were not confined during the second wave of the COVID-19 pandemic. in men, in people with low incomes and in those with a level of education below a bachelor s degree (p < 0.001). Participants who had a general feeling of good health and were not in quarantine showed less anxiety than those who felt they were in poor health and were in quarantine (p < 0.001). Furthermore, high income was an independent protective factor for anxiety (p = 0.027), and a poor state of health was an independent risk factor (p < 0.001).  In total, 18.7% presented depressive symptoms, 21.6% anxiety and 15.8% PTSD. Female sex, previous mental health problems, symptoms associated with the virus or those with an infected close relative were associated with the worst results in the three variables (p < 0.05), and age, economic stability and the information received about the pandemic were negatively correlated with symptoms (p < 0.05). Spiritual well-being was a protective factor for depression and being a student or feelings of loneliness were risk factors (p < 0.001). Low spiritual well-being, feelings of loneliness, being a woman and not enough information predicted higher anxiety (p < 0.001) and post-traumatic stress (p < 0.001).

8/8
Ferraz-Goularte et al. [32], 2020 In total, 35.5% reported stress, 32% anxiety and 34.7% depression. Single people, students, housewives, people who work in the public sector, people with a history of mental illness and those with lower educational levels were shown to be more likely to experience symptoms of stress, anxiety and depression (p < 0.05).

8/8
Massad et al. [38], 2020 Design: Quantitative cross-sectional Objective: To evaluate the prevalence of psychological distress related to quarantine and to explore sociodemographic correlations. The prevalence of mild, moderate and severe anxiety was 21.5%, 10.9% and 6%, respectively. Female gender or the presence of more members in the household were correlated with higher levels of anxiety; old age, a large social network, social support and high income correlated with lower levels. In total, 17% reported a high level of depression and 15.4% an extremely high range. Regarding anxiety, 7.2% had a high level, and 11.5% were in the extremely high range. Regarding stress, 14.6% were in the high range, and 12.6% were in an extremely high range. Female sex, having family members with COVID-19, negative affect and detachment were associated with higher levels of depression, anxiety and stress (p < 0.05). Additionally, previous medical problems were associated with higher levels of depression and anxiety, and younger people reported more stress (p < 0.05).

8/8
Ngoc Cong Duong et al. [40], 2020  Women, young people, those residing in rural areas, people with previous psychiatric illness and who did not trust government actions against COVID-19 reported higher levels of anxiety (p < 0.001).

8/8
Sherman et al. [46], 2020 Design: Quantitative cross-sectional Objective: To examine some of the burdens of the pandemic, the prevalence of mental health problems and the risk factors for psychosocial morbidity. Young people, women and participants with lower incomes were more likely to have depression and anxiety (p < 0.005), and people with a lower educational level suffered from depressive symptoms (p = 0.005). Depression was associated with previous mental illness (p < 0.0001), not being married (p = 0.008) and a greater alteration in daily life (p < 0.001). Higher levels of anxiety were linked to younger age (p < 0.005), previous mental illness (p < 0.0001) and greater disruption in daily life (p < 0.001). PTSD was associated with previous mental illness (p < 0.001) and greater disruption in daily life (p < 0.0002). PTSD. In the case of PTSD, there was a significant gender difference, with a higher prevalence in men (p < 0.01), the same situation that was observed with anxiety, but in this case with women (p < 0.01). Symptoms of anxiety, depression and PTSD were predicted by a young age, children at home and elevated risk perception. Low or loss of income and previous health problems also predicted anxiety and depression.

8/8
Smith et al. [48], 2020 Design: Cross-sectional quantitative Objective: To assess the impact of social distancing during COVID-19 on mental health. Female sex, aged 25-34 years, a lower annual income, smoke and suffering from physical multimorbidity were associated with higher levels of anxiety and depression (p < 0.05). In total, 16.5% showed moderate to severe depressive symptoms, 28.8% moderate to severe anxiety symptoms and 8.1% moderate to severe stress. Men had less PTSD but greater symptoms of anxiety, depression and stress (p < 0.05), and students demonstrated more PTSD, stress and anxiety (p < 0.05). Contact with an infected person or material was shown to be a risk factor for anxiety and depression (p < 0.01). People with lower educational levels had greater depressive symptoms (p < 0.01), and dissatisfaction with the amount of information received was associated with greater stress (p < 0.05).

8/8
Wang et al. [50], 2020 Design: Quantitative longitudinal Objective: To assess the temporary psychological impact and adverse mental health status during the initial and peak outbreak of the COVID-19 pandemic and identify risk and protective factors. To assess the effect of home confinement and social distancing resulting from the SAR-CoV-2 pandemic on the mental health of the general population, different scales and questionnaires were used. The Beck Depression Inventory (BDI), the Short Mood and Feelings Questionnaire (SMFQ), the Patient Health Questionnaire-9 (PHQ-9), the Severity of Dependence Scale (SDS), the Centre for Epidemiologic Studies Depression Scale (CES-D), the PROMIS depression v.8a and the Patient Health Questionnaire-2 (PHQ-2) were used to measure depressive symptoms. The Beck Anxiety Inventory (BAI), the Statistical Anxiety Scale (SAS), the State-Trait Anxiety Inventory (STAI), the PROMIS anxiety v.8a and the Generalised Anxiety Disorder Assessment (GAD-7), the Short version of the Whitely Index and the Health Anxiety Inventory (HAI) for health anxiety were used to assess anxiety. PTSD symptoms were evaluated by the revised Impact of Event Scale-Revised (IES-R), the reduced civilian version of the PTSD checklist (PCL-C-2), the DSM-V PTSD checklist (PCL-5) and the International Trauma Questionnaire (ITQ). The Depression, Anxiety and Stress Scale (DASS) and the Depression, Anxiety and Stress 21-item Scale (DASS-21) were used to evaluate symptoms of anxiety, depression and stress; and the Hospital Anxiety and Depression Scale (HADS) for anxiety and depression. Anxiety, stress and depression levels were measured by the DASS-21 or DASS in nearly half of the studies (n = 10), and PTSD was mostly evaluated with IES-R (n = 8). GAD-7 and PHQ-9 were also used in numerous studies to evaluate symptoms of anxiety and depression, respectively.
Regarding the statistical analysis, most studies used univariate tests to analyse the effect of sociodemographic and COVID-19-related variables on the main result of the study and multivariate tests to simultaneously analyse various study variables.
When assessing the methodological quality and risk of bias of the studies, most of them obtained high average scores, always above the set cut-off score (Tables 4 and 5).
González-Sanguino et al. [31] identified misinformation as one of the main factors that are associated with anxiety, while Lei et al. [37] demonstrated that people with more knowledge related to the COVID-19 were more likely to experience anxiety during the pandemic. The frequency of news consumption about the COVID-19 [42] and the dissemination of health information about the pandemic over radio [50] were also associated with higher scores.
Finally, taking into consideration the area of residence of the people, Özdin et al. [41] stated that living in urban areas contributed to greater anxiety, while Schweda et al. [45] found living in rural areas was associated with anxiety.
As in the case of anxiety, people with low levels of education were more likely to develop depressive symptoms than people with higher education levels [28,[31][32][33]46,47,49], except for Ripon et al. [43], who reported worse depression outcomes in people with higher educational level. Being or having been in psychiatric treatment and presenting mental health problems was also associated with the onset of depressive symptoms during home confinement and social isolation derived from the pandemic [28,[31][32][33]39,40,46]. Multivariate analyses showed that the main factors related to sociodemographic variables were being a female, young, having lower levels of education and income, or student, unemployed or housewife status; being a widower, divorcer or unmarried person; having feelings of loneliness; having previous psychiatric illness and worse self-perceived health [30][31][32]37,39,40,[46][47][48][49]. Pandemic-related variables such as concern for the COVID-19, lack of psychological support, risk perception and long periods of social distancing also contributed to the onset of depressive symptoms [30][31][32]37,39]. Protective factors, such as spiritual well-being [31], being over 60 and having a partner [39], were identified.

Discussion
Considering a global perspective, the main objective of this systematic review was to explore the mental health of the general population, in terms of depression, stress and anxiety, during social distancing and home confinement resulting from the SARS-CoV-2 outbreak. This review revealed the main factors that are associated with the development of anxiety, depression and PTSD during the pandemic, being females, young age, unemployed and people with previous mental health or psychiatric illnesses the most vulnerable.
Women developed higher levels of anxiety, stress and depression, but men also demonstrated some risk of experiencing elevated stress levels and PTSD during the COVID-19 [29,46,49]. Although women are at a lower risk of experiencing severe symptoms or even dying due to SARS-CoV-2 than men [51], they have been shown to be more vulnerable to the psychological consequences of the pandemic [52].
The perception of insufficient information was a very common factor associated with poor mental health in the revised studies, but receiving negative data has also shown high levels of anxiety [31,42,50] and stress [30][31][32]47,49], as well as concern for the pandemic. Although previous pandemic-related research showed a significant association between receiving enough information and good mental health, it has never been possible to communicate as quickly or access such immense amounts of information in real-time as today [56]. Responsible use of information dissemination and acquisition tools can help to spread scientific findings, share protocols of action and diagnosis, compare different approaches globally, provide psychological support to the population, etc. [57]; however, access to these huge amounts of information do not always involve the acquisition of reliable data, and some people may not be in a position or have the necessary skills to properly process and understand the information received [58]. Sharing fake news, conspiracy theories, magic cures and other decontextualized news increases the anxiety and stress of the population [59]. The WHO created the term "infodemic" to refer to the phenomenon by which an excessive amount of information about a problem is accessed and may be associated with inadequate public health responses and create confusion and mistrust among the population [60]. Proper management of information through reliable and verifiable sources, avoiding decontextualized use, is essential for the population to understand and adapt to the health measures dictated by the authorities [61].
The long-term implications of the previously mentioned mental health disturbances are a cause for concern. While the female gender, younger ages, lack or decrease in income, previous psychiatric illness and perception of lack of information or "infodemic" are the main factors associated with symptoms of depression, anxiety and stress, social networks and economic stability have been shown to be the main factors associated with good mental health during the pandemic [29,38,40].
All of these aspects should be considered when making government changes and implementing measures to reduce symptoms of anxiety, stress and depression. Social support and a proactive approach to the most vulnerable groups such as women, young people and people with previous mental illnesses could lead to the prevention, early detection and intervention of mental health symptoms arising from the COVID-19 pandemic [52]. Being clear about who are the people most affected by physical and social distancing measures during the pandemic facilitates the design of specific personalized self-care strategies and allows providing guidance and assistance to the most vulnerable groups of people to help and support their well-being.
To lessen the fear of a new recession and financial collapse, apart from strong and resilient leadership of the authorities, medium-and long-term planning is needed to rebalance and revive the economy [62]. In its plan for the global management of the SARS-CoV-2 pandemic, the United Nations Educational, Scientific, and Cultural Organization (UN-ESCO) highlighted the positive effect of developing clear, direct and timely information policies on the behaviour of citizens, dedicating two of its eleven ethical considerations to this subject [63]. Social media and television are the most widely used sources of information, but there is a need to improve the quality and veracity of Internet information for the general population [64]. Currently, most of the population in developed countries has access to the internet or the media, which should be used to provide specific recommendations and direct citizens to official and reliable sources.
This review provides information that will guide future research and facilitate the development of programs to alleviate pandemic-derived mental health symptoms. Knowledge of the impact of COVID-19 grows daily, so studies related to the pandemic must be continuously updated. For future investigations, these findings should be interpreted considering the limitations of this study and the revised research. The fact that all studies related to this topic were performed during the SARS-CoV-2 outbreak, the randomization of the sample may not be possible in some cases. Additionally, the online survey was the main method of information collection, being able to trigger biases in the selection of participants, such as oversampling of people with higher levels of education or younger. The absence of consideration of response rates and recruitment processes in the reviewed studies could also bias the results obtained. By removing review studies that focus on specific populations, such as health workers, people with specific diseases or the elderly, key findings related to particularly vulnerable and underrepresented communities may have been missed. Most of the studies included in the review were cross-cutting and may have assessed mental health at different stages of the outbreak, making it difficult to establish causal associations between the pandemic and the levels of depression, stress and anxiety of the population. Furthermore, although all governments based their policies on physical distancing, the measures were not the same in all countries, which may also influence the findings of the studies. Another considerable limitation is heterogeneity in the criteria used in the different studies reviewed to consider the presence of anxiety, stress and depression.
Regarding its strengths, this study identifies the most vulnerable groups of the general population, highlighting the differences between groups and identifying the factors that are associated with worse mental health. In addition, factors such as the presence of a broad social support network, receiving enough and quality information and having economic resources become particularly relevant at difficult times such as the COVID-19 social-health crisis. This scientific evidence facilitates the development of programs based on the specific needs of the general population to reduce the impact of the pandemic on its levels of stress, anxiety and depression.

Conclusions
The COVID-19 pandemic raised public health concerns not only in terms of physical health but also associated with a number of mental health disturbances. This review demonstrated that females, young age, unemployed, and patients with previous mental health or psychiatric illnesses were the most vulnerable. When disseminating information on the pandemic, governmental organisations, authorities and other professionals must use reliable and dependable sources to avoid misinformation or information overload and reduce mental health behaviours.