Background Social support has strong positive effects on health and well-being. However, social support is not equally available to all young adults and contextual effects of areas of residence like economic deprivation can negatively affect well-being. The aim of this study is to assess between-area differences in the well-being of young adults in Switzerland and the relationship with social support and economic deprivation of the area of residence.

Methods Data from the 2020-2021 subsample (n=15,770, aged 18-20) of the cross-sectional Swiss Federal Survey of Young Adults (CHX-YASS) were analysed. The questionnaire was administered either in person (men) or online (women) and included the full cohort of men of this age group. Using two-level linear regression models (individuals nested in municipality-level areas of residence), we assessed the between-area variance of well-being and its relationship with social support and economic deprivation. Well-being was measured using a modified eight-item Center for Epidemiological Studies Depression Scale (CES-D-8) ranging between 0 and 32 (higher scores indicating more symptomatology). As an indicator of economic deprivation, the unemployment rate (between 0 and 1) at the employment area level was used. The four types of social support were measured as the number of individuals providing emotional support, giving advice about school or work (informational support), providing support at work or in school (instrumental support), and serving as role models.

Results The average well-being scores varied across areas (ICC:0.067). All types of social support were positively associated with higher well-being: each additional role model was associated with a 0.27 lower CES-D score (95%CI:-0.38,-0.17), indicating better mental health. Each additional person providing informational support was associated with a 0.13 lower (95%CI:-0.21,-0.05), instrumental support with a 0.10 lower (95%CI:-0.16,-0.03), and emotional support with a 0.21 lower (95%CI:-0.26,-0.16) CES-D score. There was no evidence of gender differences. Conditioning on all four sources of support, a higher unemployment rate was associated with lower well-being (b = 0.53 95%CI:0.34,0.72). There was evidence for an interaction between gender and unemployment (b = -0.44 95%CI:-0.65,-0.22); in stratified models, the association between unemployment and CES-D were for women 0.52 (95%CI:0.3,0.73) and for men 0.1 (95%CI:-0.03,0.23).

Conclusion Consistent with existing literature on other contexts, different types of social support are related to higher well-being. There is evidence for an association between area deprivation and lower well-being among women but not among men. Due to the different sampling of men and women, these effects may in part be related to the data collection mode. The identification of unemployment rates as a significant contextual covariate underscores the need for further investigation into the substantial between-area variance in well-being, informing potential policy interventions or targeted investments.