General and Specific Social Trust as Predictors of Depressive Symptoms: Evidence from Post-Crisis Iceland

Abstract

Social trust has been linked to the development and severity of depression, but trust is a complex, multidimensional construct. This study examines the extent to which two distinct forms of trust, general trust and specific trust, predict depressive symptoms. Drawing on longitudinal data from the Directorate of Health’s national surveys conducted in 2007 and 2009, the analysis includes responses from 3211 Icelanders selected through a stratified random sample. Depressive symptoms were assessed using the Depression, Anxiety, and Stress Scale (DASS), while specific trust captured trust in close relationships, and general trust measured broader perceptions of trustworthiness in others. The two forms of trust together explained 7.6% of the variance in depressive symptoms, with specific trust contributing a substantially greater share. Both remained significant predictors after controlling for prior depression and physical health. These findings highlight the protective role of specific trust and suggest that general trust, an indicator of broader social capital, may also help buffer against depression. The results underscore the relevance of trust as a public health resource and support continued research into social determinants of mental health in Iceland.

1. Introduction

Social capital has long been considered a key pillar of well-being in Nordic societies [1,2]. It includes the networks, relationships, and trust that bind communities together and support their social and economic vitality. These connections help circulate information, promote cooperation, and create a culture of mutual support and shared purpose. Building and maintaining social capital, however, requires sustained investment in relationships, civic participation, and a culture of trust and collaboration [3,4].

Research shows that social capital, especially trust-based connections, has significant health benefits across various domains. In workplaces, high levels of trust, cohesion, and social support are linked to improved psychological and physical health, higher job satisfaction, and greater organizational resilience [5,6,7,8,9]. These effects reflect a broader pattern found internationally, where social trust is positively associated with good health outcomes [10,11], particularly in the domain of mental health [12,13].

In Iceland, mental health has become an increasing public health concern. Reports indicate rising symptoms of depression [14], increased antidepressant use [15], and a documented decline in social capital following the 2008 financial crisis [16].

Although social capital is widely recognized as a determinant of health, few studies in Iceland have directly examined its relationship with mental health. This research gap is especially important given Iceland’s unique social and economic context. The 2008 financial crisis deeply affected trust in both institutions and interpersonal relationships, making this period a compelling setting for studying the link between social trust and mental health. Beyond financial collapse, the crisis also strained everyday life and social cohesion in Iceland. Rising unemployment, housing insecurity, and widespread protests reflected not just economic hardship but also public frustration, fear, and social fragmentation. These conditions disrupted informal support networks and may have intensified psychological vulnerability across segments of the population. This study addresses that gap by examining whether depressive symptoms are associated with social trust among participants in the 2007 and 2009 Health and Wellbeing of Icelanders surveys.

A growing body of international research has documented how the 2008 financial crisis affected mental health, highlighting the importance of social trust and support systems during times of economic upheaval. In Spain and Greece, the crisis was linked to marked increases in psychological distress, depression, and suicide, particularly among individuals affected by unemployment and housing insecurity [17,18]. In the United Kingdom, mental health deteriorated following austerity measures, especially among working-age women [19]. In the United States, research based on the Fragile Families and Child Wellbeing Study showed that job loss and financial strain during the recession significantly increased depressive symptoms, particularly when social support was lacking [20]. These international findings highlight the psychosocial toll of financial crises and support the importance of studying how trust and mental health interact during such disruptions.

Although the Icelandic financial crisis provides a distinctive context for examining the mental health effects of social trust, similar dynamics have emerged in many other countries over the past decade. Generalized trust has declined across numerous democracies, a trend linked to increasing political polarization, the rise of populist movements, and the spread of misinformation [21,22]. This erosion of trust has coincided with broader democratic backsliding and growing public disillusionment with democratic institutions, especially among younger generations [23,24]. These developments have sparked renewed concern about the societal and psychological consequences of trust erosion. Iceland’s post-crisis experience thus offers timely insights into how both generalized and specific forms of trust relate to mental health in the wake of systemic disruption.

Emerging evidence from post-crisis settings also demonstrates that social trust and cohesion can not only erode following major shocks, but may also rebound, supporting societal resilience and public health. For example, the World Happiness Report [25] documented an increase in social trust during the COVID-19 pandemic, and Silveira et al. [26] observed dynamic shifts in social cohesion and resilience across pandemic phases. These findings suggest that Iceland’s post-2008 experience may foreshadow patterns of social trust change in other societies, helping to inform our understanding of how trust and mental health co-evolve in the face of contemporary crises.

Depression is a common mental health condition that affects people across different ages and backgrounds. Most individuals experience symptoms of depression at some point in their lives. During such times, strong social support can help prevent temporary sadness from developing into prolonged depression. Social networks offer emotional support, practical help, and a sense of belonging, all of which play a vital role in mental well-being. Supportive relationships, especially in times of hardship, can be a powerful source of encouragement during recovery. For instance, socially isolated individuals are more likely to experience long-term sadness [27]. In contrast, having access to strong social connections has a clear positive effect on mental health [28,29,30]. This is especially true in workplace settings, where support from colleagues and supervisors can reduce stress and improve job satisfaction [31].

Strong social connections, however, are fundamentally built on trust. Trust forms the basis of interpersonal relationships and social cohesion. It involves the belief and expectation that others act with sincerity, honesty, and goodwill, without causing harm and ideally protecting the interests of the trusting person [32,33,34]. Trust is essential for maintaining relationships and enabling cooperation, as it reduces uncertainty and encourages people to engage with one another. Without trust, meaningful or constructive relationships are difficult to form [35]. Support in difficult times may also fail if the recipient does not believe it is being offered sincerely or with good intentions. Trust, then, is not just a social nicety, but a core element of positive and resilient relationships. Unsurprisingly, individuals who trust others are more likely to form close connections, which in turn contribute to their overall mental well-being [36].

Trust also appears to have an independent link to both physical and mental health. For example, people with higher levels of trust tend to live longer [37] and report fewer symptoms of psychological stress [38]. In addition, research shows that trust in close relationships and in the workplace can reduce symptoms of depression and anxiety [9,39]. These findings highlight the value of building trust not only in personal relationships but also within larger social and organizational settings.

Social trust is often divided into two types: specific trust and generalized trust [32]. Specific trust develops through close or repeated interactions and is based on personal experience. Examples include trust between a therapist and client [40,41], or between close friends and family members [39]. This kind of trust is formed over time and is often seen as the foundation of strong, supportive relationships. In many theoretical models, specific trust is considered a developmental precursor to generalized trust, which reflects broader expectations about how trustworthy people are in general [32]. In contrast, generalized trust refers to a person’s overall outlook on whether others can be trusted [42]. Unlike specific trust, it is not based on personal experience and may extend to strangers or groups outside one’s immediate social circle. Generalized trust plays a key role in how societies function, as it encourages cooperation and reduces conflict among people who do not know each other. The relationship between these two types of trust may be shaped by cultural and institutional factors. In long-term-oriented, high-trust societies like Iceland, specific trust may more readily generalize to wider social expectations, potentially enhancing resilience in the face of disruption. The WHO’s European Region [42] emphasizes the importance of building trust between key stakeholders, such as governments, the media, and individuals, in its public health strategy. Similarly, the Icelandic government views trust in fellow citizens and in the political system as indicators of prosperity and quality of life [43].

Although trust is clearly important, few studies have explored how depression may be linked to generalized and specific trust. This question is especially relevant in Iceland, where the 2008 financial crisis significantly undermined societal trust. Researchers have documented declines in trust in institutions, such as the government and media, as well as in interpersonal relationships, during that period [44,45,46]. This situation offers a unique opportunity to study how changes in trust may influence mental health.

The aim of this study is to examine how generalized and specific trust relate to depressive symptoms, contributing to a better understanding of the social factors that shape mental well-being. Based on prior research, I hypothesize that higher levels of both specific and generalized trust will be associated with fewer depressive symptoms, with specific trust expected to be the stronger predictor.

2. Materials and Methods

2.1. Participants and Procedure

This study uses data from the Health and Wellbeing of Icelanders surveys, conducted by the Directorate of Health in 2007 and 2009. The goal of these surveys was to collect detailed information on the physical and mental health of Icelandic citizens, along with a range of social and demographic variables. Both surveys received ethical approval from the National Bioethics Committee (reference numbers 07-091 and 09-094) and were reported to the Icelandic Data Protection Authority to ensure compliance with data protection regulations [47,48].

For the 2007 survey, a stratified random sample of Icelandic citizens was drawn, with stratification based on age and geographic location to ensure a representative cross-section of the population [47,48]. This approach helped minimize sampling bias and enhanced the generalizability of the findings to the wider Icelandic population. The sample included 9807 individuals, of whom 5909 responded, resulting in a response rate of 60.3%. To improve participation, the survey was distributed both online and on paper, allowing respondents to choose their preferred format.

Respondents from the 2007 survey were invited to participate in a follow-up study in 2009. Of those originally surveyed, 5411 agreed to take part, reflecting a strong level of engagement. In November 2009, the Directorate of Health sent questionnaires to 5294 individuals, adjusting for attrition due to relocation or loss of contact. The follow-up achieved a high response rate of 77.3%, with 4092 individuals completing the questionnaire.

The final sample included 3211 individuals who provided complete responses on all variables used in the analysis, across both the 2007 and 2009 surveys. Respondents with missing data on any analytic variable were excluded. While this approach ensures internal consistency across regression models, it may introduce some bias. Specifically, individuals who dropped out of the panel between 2007 and 2009, or who failed to answer all relevant items in 2009, may differ systematically from those who remained in the study. For example, prior research suggests that individuals with poorer mental health or lower social trust may be more likely to disengage from follow-up surveys, potentially leading to an underestimation of associations with depressive symptoms [49,50,51,52]. The comprehensive design of the surveys and the data collection process ensured coverage of a broad range of demographic, social, and health-related variables, allowing for a robust examination of the relationships explored in this research.

All data were anonymized prior to analysis. An independent data custodian handled the matching of participant records across the 2007 and 2009 surveys. Personal identifiers (such as national ID numbers) were stored separately and never shared with the research team. The final analytical dataset contained only anonymized information, ensuring full compliance with ethical and data protection standards [47,48].

2.2. Measures

This study used several validated instruments to assess depressive symptoms, social trust, and a range of demographic and health-related variables. For clarity, the measures are grouped by their analytic roles. Depressive symptoms in 2009 served as the dependent variable. The primary independent variables were specific trust and generalized trust. Control variables included prior depression (diagnosed in 2007), self-rated physical health, and demographic characteristics (gender, age, education, employment status, and marital status). These controls were selected because prior research shows they are strongly associated with depression, particularly in the context of economic disruption. For example, studies during and after the 2008 financial crisis found elevated depressive symptoms among individuals who were unemployed [20], in poor physical health [18], or experiencing socioeconomic disadvantage [17,19]. Including these variables in the model allows for a more accurate estimation of the unique contribution of social trust.

Depressive symptoms in 2009 were measured using the Depression, Anxiety, and Stress Scale (DASS) [53], a widely used psychometric instrument for assessing symptom severity. For this study, the 14-item depression subscale, translated into Icelandic by Pétur Tyrfingsson, was used. Participants rated their agreement with each statement on a four-point Likert scale: 0 (did not apply to me at all), 1 (applied to me to some degree or sometimes), 2 (applied to me to a considerable degree or often), and 3 (applied to me very much or most of the time). Total scores were calculated by summing all responses, yielding a possible range from 0 to 42, with higher scores indicating more severe symptoms. The scale showed excellent internal consistency in this sample (Cronbach’s alpha = 0.94). In contrast, prior depression in 2007 was assessed with a single, dichotomous item asking participants whether they had ever been diagnosed with depression by a physician or psychologist. The DASS was not included in the 2007 survey, and this diagnostic item was the only available measure of prior depression. While the item lacks the nuance of a symptom-based scale, it offers a clinically grounded indicator of mental health history. Because it reflects a diagnosis by a trained professional, it may be considered more conservative and specific than self-reported symptoms. Nevertheless, as it captures a binary outcome rather than symptom severity, it is not directly comparable to the continuous DASS scale used in 2009.

Education level was classified into three categories based on the highest level of education completed: (1) primary education, including elementary or lower secondary school; (2) secondary education, covering vocational training, technical college, or other qualifications below a bachelor’s degree; and (3) higher education, including bachelor’s, master’s, or doctoral degrees. This categorization allowed for the examination of how educational attainment may influence health and trust outcomes.

Employment status was categorized into three groups: employed, unemployed, and retired. These categories reflected participants’ engagement in the labor market and provided context for analyzing the relationship between employment, depressive symptoms, and trust.

Marital status was grouped into four categories: (1) in a committed relationship, including married, cohabiting, or partnered; (2) divorced; (3) widowed; and (4) single. This variable was used to examine how relationship status may influence mental health and social trust.

Physical health was assessed through self-report. Participants rated their general physical health as very good, good, fair, or poor. This subjective measure served as a broad indicator of overall well-being and enabled comparisons across different health levels.

Specific trust was measured by asking participants how easy or difficult they found it to trust four groups: spouse or partner, other family members, friends, and coworkers or classmates. Responses were recorded on a five-point scale: 1 (very difficult), 2 (somewhat difficult), 3 (neither easy nor difficult), 4 (somewhat easy), and 5 (very easy). A mean score was calculated across all four items, ranging from 1 to 5, with higher scores indicating greater specific trust. The scale showed good internal consistency (Cronbach’s alpha = 0.82). This measure reflected trust in close social relationships, a key component of social capital.

General trust was measured using six statements that participants rated in terms of agreement or disagreement. These included: (1) most people can be trusted (reverse-coded), (2) you have to be very cautious in dealing with people, (3) most people would take advantage of me if given the chance, (4) most people try to be fair (reverse-coded), (5) people generally try to be helpful (reverse-coded), and (6) people mostly look out for themselves. Three items were reverse-coded to ensure scoring consistency. A mean score was calculated across all six items, with possible values ranging from 1 to 5; higher scores indicated greater general trust. This measure demonstrated good internal consistency (Cronbach’s alpha = 0.80) and reflected an individual’s general view of the trustworthiness of people beyond their close social networks.

The 2007 and 2009 surveys included many of the same items, allowing for the use of baseline covariates. However, the primary outcome variable, depressive symptoms measured by the DASS, was only administered in the 2009 survey. As a result, the study uses a cross-sectional design focused on 2009, with selected variables from the 2007 survey (e.g., prior depression diagnosis, demographic variables, physical health) used as control variables. Although trust, physical health, and employment status were measured in both waves, the absence of repeated outcome data precluded a longitudinal analysis of change in depressive symptoms.

2.3. Data Analysis

To analyze the relationship between depressive symptoms and the independent variables, hierarchical multiple regression was used. This approach allowed for a step-by-step evaluation of how different sets of predictors contributed to explaining the variance in depressive symptoms.

In the first step, demographic variables, gender, age, education, employment status, and marital status, were entered into the model. In the second step, general physical health was added to account for its potential effect on depressive symptoms. The third step introduced prior depression (based on 2007 diagnosis) as an additional predictor. In the final step, specific and general trust were added to assess their unique contributions beyond the previously entered variables.

All assumptions for the regression analysis, linearity, homoscedasticity, and absence of multicollinearity, were tested and satisfied. The stepwise inclusion of variables allowed for a clear interpretation of each predictor’s contribution to the overall model. Results are reported as standardized regression coefficients (β) to enable comparison across predictors.

All analyses were conducted using IBM SPSS Statistics version 28. Statistical significance was set at p < 0.05.

3. Results

The demographic characteristics of the sample are summarized in

Table 1. Demographic characteristics of the sample (N = 3211).

Independent Variables	Weighted %	N
Gender
Women	47.8	1536
Men	52.2	1675
Education
Primary	29.4	944
Secondary	37.4	1200
Tertiary (University)	33.2	1066
Employment status
Employed	83.7	2687
Unemployed	5.5	176
Retired	10.8	347
Marital status
In a relationship	80.8	2596
Divorced	5.0	162
Widowed	2.6	83
Single	11.5	370
Self-rated physical health
Very good	32.7	1050
Good	49.7	1595
Fair	15.4	494
Poor	2.3	72
Diagnosed depression in 2007
No diagnosis	96.8	3110
Diagnosed depression	3.2	101

. In 2009, the mean age of participants was 46 years, representing a middle-aged population and providing a balanced cross-section of Icelandic adults. Most participants had completed education beyond the primary level, with substantial portions reporting secondary or higher education. The majority were employed, while smaller groups were unemployed or retired. A large proportion reported being in a committed relationship, including those who were married, cohabiting, or in partnerships. These demographic and social variables provide important context for interpreting the subsequent analyses.

Regarding health characteristics, most participants reported good physical health, consistent with previous studies on Icelandic populations. Just over 3% indicated having been diagnosed with depression by a physician or psychologist in 2007, suggesting a relatively low prevalence of clinically recognized depression at that time. In 2009, the mean score on the DASS depression subscale was slightly below 4, aligning with findings from earlier Icelandic research [53]. These results indicate consistency in the levels of depressive symptoms observed across studies (

Table 2. Means and standard deviations for depression, age, and trust (N = 3211).

Variables	M	SD	N
Depressive symptoms—DASS	3.73	6.03	3211
Age (in years)	45.85	15.24	3211
Specific trust	3.76	0.84	3211
Generalized trust	3.50	0.59	3211

).

Table 3. Multiple regression analysis predicting depressive symptoms from all independent variables (N = 3211).

Independent Variables	b	SE	Standardized b	t	p
Gender and age
Women (reference group)
Men	−0.50	0.19	−0.04	−2.65	0.008
Age	−0.03	0.01	−0.08	−3.96	<0.001
Education
Primary (reference group)
Secondary	−0.05	0.23	0.00	−0.21	0.837
Tertiary (University)	−0.12	0.24	−0.01	−0.51	0.609
Employment status
Employed (reference group)
Unemployed	1.78	0.41	0.07	4.35	<0.001
Retired	−0.19	0.39	−0.01	−0.50	0.615
Marital status
In a relationship (reference group)
Divorced	1.30	0.42	0.05	3.07	0.002
Widowed	1.37	0.60	0.04	2.27	0.023
Single	1.74	0.30	0.09	5.76	<0.001
Self-rated physical health
Very good (reference group)
Good	0.58	0.21	0.05	2.76	0.006
Fair	3.10	0.30	0.19	10.46	<0.001
Poor	5.49	0.65	0.14	8.49	<0.001
Diagnosed depression in 2007
No diagnoses (reference group)
Diagnosed depression	7.29	0.54	0.21	13.49	<0.001
Trust measures
Specific trust	−1.65	0.12	−0.23	−14.26	<0.001
Generalized trust	−1.33	0.17	−0.13	−7.93	<0.001

shows the relationships between depressive symptoms and the independent variables, including specific and general trust. Most of the associations were statistically significant, indicating that the included variables meaningfully contributed to explaining depressive symptoms. One exception was education level, which did not show significant differences across categories. This suggests that, in this sample, educational attainment may not be directly related to depressive symptoms.

The analysis revealed several notable trends after controlling for other independent variables. Women reported more depressive symptoms than men, consistent with previous research on gender and mental health. Depressive symptoms also declined with age, indicating that older participants were less likely to report symptoms than younger ones. Employment status had a clear impact: unemployed individuals reported significantly higher levels of depressive symptoms than those who were employed, reflecting the psychological burden of unemployment. Relationship status was also associated with mental health outcomes. Participants in committed relationships reported fewer depressive symptoms than those who were divorced, widowed, or single, highlighting the potential protective effects of close interpersonal bonds.

Physical health was also a strong predictor of depressive symptoms. Participants who rated their physical health as less than “very good” reported higher levels of depressive symptoms, with symptom severity increasing as self-rated health declined. This finding highlights the close connection between physical and mental well-being. In addition, participants diagnosed with depression by a physician or psychologist in 2007 reported significantly more depressive symptoms in 2009 than those without such a diagnosis, underscoring the persistent nature of depression over time.

Both specific and general trust were significant predictors of depressive symptoms. Higher levels of each were associated with fewer symptoms, reinforcing the role of trust in supporting mental health. However, specific trust showed a stronger association than general trust. This suggests that trust in close relationships, such as with family, friends, or coworkers, may have a more direct and immediate effect on reducing depressive symptoms than broader, generalized trust.

Notably, both prior depression and specific trust were strong predictors of depressive symptoms in 2009. While the DASS scale used to assess symptoms in 2009 offers a continuous and sensitive measure of severity, the prior depression variable reflects a binary self-report of physician-diagnosed depression in 2007. Although this diagnostic item has clinical specificity, it does not capture symptom severity in the same way. With these differences in mind, the results suggest that trust in close relationships is a robust and meaningful correlate of mental health, even when accounting for a history of diagnosed depression. This finding supports the value of specific trust as a potential target for mental health interventions and highlights the protective role of supportive social connections.

Table 3 presents the final model (Step 4) of the hierarchical multiple regression analysis. The regression process proceeded in four steps, with each step introducing new sets of predictors. Step 1 included demographic variables, gender, age, employment status, education, and relationship status, which served as the baseline for understanding how individual characteristics relate to depressive symptoms.

In Step 2, general physical health was added to capture the influence of participants’ overall physical well-being on depressive symptoms. Step 3 introduced prior depression (diagnosed in 2007) as an additional predictor, accounting for the impact of previous mental health conditions. In the final step, Step 4, specific and general trust were included to assess their unique contributions beyond the other variables in the model.

Table 4. Explained variance in depressive symptoms by stepwise addition of independent variables (N = 3211).

Independent Variables		Adjusted R2	ΔR2	p
Step 1	Gender, age, employment status, education, and marital status	6.5%	6.5%	<0.001
Step 2	Adding self-rated physical health	14.1%	7.6%	<0.001
Step 3	Adding depression diagnosis in 2007	19.5%	5.4%	<0.001
Step 4	Adding specific and generalized trust	27.1%	7.6%	<0.001

summarizes the variance explained at each step of the regression analysis. In the final model, the independent variables collectively accounted for 27.1% of the variance in depressive symptoms. Demographic factors explained the initial portion, while general physical health and prior depression contributed an additional 13%. Specific and general trust explained a further 7.6%, with specific trust accounting for a substantially greater share than general trust. This result underscores the importance of trust, particularly in close relationships, in understanding and addressing depressive symptoms.

4. Discussion

The findings of this study highlight the important role that trust plays in shaping depressive symptoms. Both specific and general trust emerged as significant predictors, contributing beyond the effects of prior depression and self-rated physical health. These results underscore the multifaceted nature of trust and its relevance for understanding and addressing depression.

Specific trust showed a particularly strong association with depressive symptoms, consistent with prior research highlighting the role of social support in mental health [11]. This type of trust, referring to confidence in close relationships with family, friends, and coworkers, appears to provide a direct protective effect against depression [9,36,39]. It enables emotional and practical support that can buffer against stressors likely to trigger or intensify depressive symptoms. The strength of this association reinforces the importance of prioritizing trusting relationships in mental health promotion and prevention.

Notably, the effect of specific trust was comparable in magnitude to that of a prior clinical diagnosis of depression, suggesting that trust in close relationships may serve as a meaningful protective factor even among individuals with elevated baseline risk. This finding underscores the practical value of fostering strong interpersonal connections in mental health promotion, particularly in post-crisis contexts. Enhancing specific trust through community-based interventions or support programs could offer a low-cost complement to clinical care for preventing or alleviating depressive symptoms.

Interestingly, education level was not a significant predictor of depressive symptoms in this sample. One possible explanation is that Iceland has relatively low income inequality and high educational attainment across the population, which may attenuate the mental health differences typically associated with education. Alternatively, in the context of an economic crisis, the protective effects of education may be overshadowed by more immediate stressors, such as unemployment or declining social support.

Although weaker than specific trust, general trust also contributed independently to depressive symptoms, highlighting its distinct role. General trust reflects a person’s belief in the trustworthiness of others, including strangers and institutions [32]. It can serve as a coping resource, especially when specific trust is limited, by encouraging openness to seeking help from sources such as healthcare providers or support services, even in the absence of prior relationships. This willingness to engage with others is critical for early intervention and recovery.

The broader societal value of general trust is also noteworthy. Prior studies have linked it to self-rated health [54], and its influence may extend to mental health by shaping perceptions of safety, fairness, and cohesion within communities. These perceptions, in turn, foster stability and support, conditions conducive to psychological well-being.

Nonetheless, the possibility of reverse causation must be acknowledged. Individuals experiencing depressive symptoms may be less inclined to trust others, perhaps due to social withdrawal, past rejection, or trauma. Depression may impair one’s ability to view others as trustworthy, creating a feedback loop in which diminished trust reinforces feelings of isolation and hopelessness. Future research should examine these bidirectional dynamics to better understand the complexity of the relationship between trust and depression.

Despite such complexities, the public health relevance of general trust remains clear. It is widely considered a core component of social capital, the networks, norms, and trust that enable cooperation and mutual support. Social capital has been shown to buffer against common mental disorders [55,56], and policymakers have increasingly recognized its value in efforts to strengthen social cohesion and quality of life [43,57,58].

The burden of depression is substantial, both in Iceland and globally. In Iceland, mental disorders are the leading cause of disability assessments, with prevalence and impact increasing over the past decade [59,60,61]. This trend reflects global patterns, where depression is a leading cause of disability [62], affecting over 350 million people worldwide [63,64]. These figures underscore the urgent need for effective and scalable strategies to address depression at multiple levels [65].

International organizations, such as the WHO and OECD, have emphasized integrating social support systems and networks into mental health policy [66,67]. The present findings support this approach, suggesting that both specific and general trust are valuable public health resources. In the Icelandic context, ongoing monitoring of depression prevalence is critical for effective public health planning. Without such data, the true scope of the problem remains unclear, limiting the ability to track trends or evaluate the impact of policy [68].

Beyond the psychological toll, depression imposes considerable social and economic costs, lower productivity, lost work hours, absenteeism, and long-term disability. While pharmacological treatments can be effective, they are costly and often accompanied by side effects that reduce adherence [69]. These challenges highlight the importance of low-cost, scalable interventions that harness existing social resources.

One promising approach lies in strengthening societal coping resources, particularly those embedded in workplaces and communities. Research points to the value of supportive environments in mitigating mental health challenges [70,71,72]. Trust-building interventions, such as peer support, group activities, and public awareness campaigns, may offer accessible and sustainable ways to reduce depressive symptoms.

These findings align closely with broader themes of sustainability and societal adaptation. As Riemer et al. [73] argue, navigating systemic crises requires adaptive, collective frameworks that can rebuild trust and institutional capacity in the face of complex change. Similarly, O’Hara [74] emphasizes the role of functioning institutions and social cohesion in balancing societal interests amid large-scale threats such as climate change. At the individual level, recent work by Saghin et al. [75] has shown how psychological resilience and mental health are critical dimensions of a society’s ability to cope with disruption. Although this study draws on data from the 2008 financial crisis, the dynamics it explores, erosion and restoration of trust, and their mental health consequences, remain highly relevant. Similar patterns have been observed during more recent crises, including the COVID-19 pandemic and ongoing democratic backsliding. In this light, the Icelandic case offers timely insights into how trust functions as social infrastructure, supporting psychological well-being and enhancing societal sustainability in times of upheaval.

The strong predictive role of specific trust reinforces the value of fostering interpersonal relationships within families, friendships, and workplaces. Promoting open communication, mutual respect, and shared goals in these settings can help build the trust necessary to support psychological well-being. Likewise, the independent contribution of general trust highlights its broader relevance. Strengthening institutional trust through transparency, fairness, and accountability in governance, media, and public services may improve mental health while also enhancing social cohesion and resilience.

Future research is needed to further examine how social trust interacts with mental health. Studies should investigate the mechanisms through which trust exerts its influence and assess the effectiveness of interventions aimed at enhancing trust. Longitudinal designs are especially important for clarifying the directionality of the relationship between trust and depression and for tracking these dynamics over time.

The extent to which these findings generalize beyond Iceland also warrants consideration. Iceland is a relatively small and cohesive society with historically high levels of both institutional and interpersonal trust. These contextual features may have amplified the protective effects of specific trust in this setting. In larger, more heterogeneous, or lower-trust societies, the relationship between trust and depressive symptoms may differ. For example, in settings marked by higher inequality or institutional distrust, diminished trust could compound psychological vulnerability rather than buffer against it. Future studies should therefore examine how cultural norms, political institutions, and patterns of social cohesion may moderate the association between trust and mental health. A clearer understanding of these boundary conditions is essential for assessing how broadly these findings apply.

Limitations

Several limitations should be considered when interpreting these findings. First, while the study draws on data from both 2007 and 2009, the outcome measure, depressive symptoms, was assessed only in the 2009 survey using the DASS scale. As a result, the analyses are cross-sectional with respect to depressive symptoms, and causal inferences cannot be made. Second, the 2007 measure of prior depression was based on a single self-reported physician diagnosis, which lacks the nuance of a symptom-based scale. This discrepancy in measurement limits comparability and should be interpreted cautiously. Third, the analytic sample was restricted to participants with complete data on all relevant variables. Although this approach ensures consistency across models, it may introduce selection bias. Individuals with poorer mental health or lower social trust may have been more likely to disengage from follow-up surveys or skip key items, potentially underestimating associations with depressive symptoms [49,50,51,52]. Finally, while the sample is population-based, the findings may not generalize to larger or lower-trust societies, as discussed above. Despite these limitations, the study provides valuable insights into the relationship between social trust and mental health during a period of national disruption.

Although the study draws on data from both 2007 and 2009, the analysis is cross-sectional in design. Depressive symptoms were measured only in the 2009 survey using the DASS scale, which precluded modeling change in mental health over time. While some key predictors, such as trust, physical health, and employment status, were measured in both years, the analytic focus was on explaining depressive symptoms at a single time point, using selected variables from the earlier wave as controls. The study is thus best interpreted as capturing associations during a specific period of post-crisis adjustment, rather than longitudinal change.

In conclusion, this study underscores the significance of social trust in shaping depressive symptoms. Both specific and general trust contribute independently to mental health outcomes, offering complementary avenues for intervention. As recognition of the social determinants of mental health grows, trust stands out as a powerful, modifiable protective factor.

These findings are especially relevant in the Icelandic context, where the 2008 financial crisis profoundly disrupted both institutional and interpersonal trust. Research has documented a decline in social capital during this period, suggesting that the erosion of trust may have lasting mental health consequences [16,44,55,56]. In a small and socially cohesive society like Iceland, even modest changes in trust may ripple widely through communities. This study provides evidence that shifts in generalized and specific trust are not only social phenomena but also key determinants of population-level mental well-being.

5. Conclusions

This study adds to the growing literature on the social determinants of mental health by examining the relationship between generalized and specific trust and depressive symptoms in the unique context of post-crisis Iceland. By addressing a notable gap in Icelandic research, the findings emphasize the dual role of social trust, both as a protective factor against mental distress and as a foundation for societal resilience in times of upheaval. These results have important implications for public health policy, underscoring the need to foster trust and strengthen social capital to mitigate the psychological effects of socio-economic disruption. As Iceland continues to confront the long-term aftermath of the 2008 financial crisis, this research highlights the transformative potential of rebuilding and sustaining trust as a cornerstone of population well-being and national recovery.

The findings of this study highlight the potential of social trust, particularly specific trust, as a modifiable social determinant of mental health. Public health strategies in Iceland could benefit from incorporating trust-building efforts into mental health promotion and prevention initiatives. Community-based programs that foster interpersonal trust through peer support, group activities, and workplace cohesion may provide accessible and low-cost ways to reduce depressive symptoms and strengthen societal resilience. In addition, trust in institutions and among citizens could be supported through policies that emphasize transparency, fairness, and accountability in public services. While grounded in the Icelandic context, these insights may also apply to other small, high-trust societies facing social disruption, highlighting the global relevance of trust as a public health resource [76].