The two studies lend support for a model where perceived stress mediates the association of negative life events with more severe depressive symptoms. This aligns with a previous meta-analysis11 and supported by other studies focusing on the link between life events and depressive symptoms in students7, emerging adults18 and the maternal population17. Additionally, negative life events, specifically family and social problems, were observed to be directly associated with levels of perceived stress24.
The university population showed a serial mediation from the occurrence of negative life events to their perceived impact on current mood to perceived stress to depressive symptoms, however in mothers from the Growing Up in Singapore Towards healthy Outcomes (GUSTO) study, occurrence and impact each were mediated by perceived stress, but occurrence was not mediated by impact. This might be explained by the high collinearity between occurrence and impact of negative life events in the GUSTO mothers (r = .94), differences between impact on current mood in study 1 instead of perceived impact of the life event in study 2 or differences between populations in specific cognitive vulnerabilities25. Previous research found that ruminative thinking and worry due to stressful life events led to increased depressive symptoms in young adolescents4. Moreover, depressive symptoms have been associated with chronic strain related to negative life events among mothers22.
Social support was consistently protective against depressive symptoms among participants with higher levels of stress across both studies. This is once again consistent with the findings of previous studies26. In high stress, when an individual’s capacity to manage independently is exceeded, social support may become critical to raise their ability to cope13. Notably, we found that social support only moderated the association between perceived stress and depressive symptoms, suggesting a ‘late buffering’ effect in our mediation model. Social support showed no moderation of the association between the occurrence and impact of negative events, andno associations between negative life events and perceived stress. This may indicate that social support buffers the affective impact of stress that one perceives from a life event. Specifically, an individual with high social support may still perceive and experience the same level of stress from an adverse life event, but is able to handle the consequences of such stress and regulate their emotions, or may be less prone to depressive cognitions such as helplessness and personalisation27,28.
In the study 1 university population, there was only a buffering effect from the social support of friends and significant others; however, in the study 2 mothers, there was only a buffering effect from the social support of family and significant others.Youth have been shown to seek out peers rather than family for social support reflecting a developmental focus on intimacy29, while mothers may be more satisfied with support from their parents than support from their friends when experiencing struggles in parenting30,31. In Singapore, instrumental support often from grandparents and perceived conflicts with relatives have been shown to predict perinatal depression32. Studies involving mothers that returned no significant moderating effects tended to combine the scores of social support from multiple sources, possibly due to the dilution of instrumental or familial support20–22 .
In terms of strengths, our studies provide a comparison of the stress-buffering effect of social support between two Singapore populations. Furthermore, the moderated mediation finding where social support buffers against depression in the presence of high stress was replicated across both studies, despite substantive differences in life stages and likely stressors between populations. Additionally, the demographic fills an important gap as other Singapore studies on social support in depression has focused on the elderly population33,34, although the youth age group of 18 to 34 years comprised the majority of depression cases in the local context35. In terms of limitations, in study 1, life events were recalled retrospectively at the same time as depressive symptoms, while in study 2, depressive symptoms were examined 1.5 years after the measurement of stressful life events over a one-year period. This supports a temporality of stressors preceding depression, but would be better supported with repeated measures over time. Some of the differences in measures, timepoints and populations may add complexity when comparing between studies.
The results of the present study have important practical implications. By understanding how stressful life events are related to depression and the pathway by which such events influence depressive symptoms, self-report measures of stressful life events and perceived stress may be used as a proxy to identify people who are at risk of depression, and offer preventative resources to reduce their likelihood of developing clinical depression. By adding clarity to how social support buffers against depression and which forms of social support are important in which populations, our study may inform the application of social support-based interventions36. Our findings support existing literature highlighting the stress-buffering role of social support in alleviating the adverse effects of stress, during stressful periods such as COVID-1937, and pregnancy38.
Furthermore, by examining the exact locus of the buffering effect social support on life events and depression, researchers and clinicians may provide more targeted advice to caregivers of those who are significantly emotionally impacted by life events. For example, social support was found to moderate the relationship between perceived stress and depression at an earlier stage in the pathway, which may imply that social support might be better for coping with stress arising from life events. Additionally, given the differing locus of the stress-buffering effect of social support found in our studies, there could be more nuances in evaluating individuals’ vulnerability to depression and the designing of the interventions with clients. For instance, mothers might want to assess how family members support them, and how their family members can be involved in the therapy trajectory. For youth, they might want to assess the social support among peers and romantic partners and work towards expanding social support among similarly aged individuals.
In summary, our study offers nuanced insights into the relationship between negative life events, perceived stress, and social support, and their impact on depressive symptoms across different populations in Singapore. Our findings emphasise the stress-buffering role of social support in alleviating depressive symptoms, particularly during periods of heightened stress. The differential impact of social support in both studies emphasise the need for tailored interventions that consider unique social support preferences in various demographic contexts. Finally, our findings contribute to a more complex understanding of an individual's vulnerability to depression, which may have practical implications in the development of effective and personalized mental health interventions for diverse populations.