Kiely, KimSutherland, GeorginaButterworth, PeterReavley, N2022-11-180933-7954http://hdl.handle.net/1885/280329Purpose To examine (i) reciprocal longitudinal associations between social connectedness and mental health, and (ii) how these associations vary by age and gender. Methods Three waves of nationally representative data were drawn from the HILDA survey (n = 11,523; 46% men). The five-item Mental Health Inventory (MHI-5) assessed symptoms of depression and anxiety. The Australian Community Participation Questionnaire provided measures of informal social connectedness, civic engagement and political participation. Multivariable adjusted cross-lagged panel regression models with random intercepts estimated bidirectional within-person associations between mental health and each of the three types of social connectedness. Multi-group analyses were used to quantify differences between men and women, and between three broad age groups (ages: 15–30; 31–50; 51+). Results Reliable cross-lagged associations between prior informal social connections and future mental health were only evident among adults aged 50 years and older (B = 0.101, 95% CI 0.04, 0.16). Overall, there was no significant association between prior civic engagement and improvements in mental health (p = 0.213) though there was weak evidence of an association for men (B = 0.051, 95% CI 0.01, 0.09). Similarly, there was no significant association in the overall sample between political participation and improvements for mental health (p = 0.337), though there was weak evidence that political participation was associated with a decline in mental health for women (B = − 0.045, CI − 0.09, 0.00) and those aged 31–50 (B = − 0.057, CI − 0.10, − 0.01). Conversely, prior mental health was associated with future informal social connectedness, civic engagement, and political participation. Conclusion Interventions promoting social connectedness to improve community mental health need to account for age- and gender-specific patterns, and recognise that poor mental health is a barrier to social participation.application/pdfen-AU© 2020 The authorsMental healthCivic engagementSocial connectednessPolitical participationRandom-intercept cross lagged panel regression202010.1007/s00127-020-01960-32021-11-28