AbstractBackgroundSeveral protective factors have been identified for mental health (MH) resilience in adolescent offspring of depressed parents. However, it is unclear if these effects persist into adulthood.MethodsDepressed parents and their offspring (N = 188) from the Early Prediction of Adolescent Depression study were assessed four times (mean offspring ages 12.39, 13.77, 14.82, and 23.41). Mental health resilience was examined using residual scores (betterâthanâexpected moodâ, behaviourâ, or anxietyârelated MH at mean age 23 given risk exposure), and categorically as sustained good MH across adolescence and young adulthood.ResultsOnly 9.2% of young adults demonstrated sustained good MH. Parents of resilient individuals showed lower comorbidity (anxiety, antisocial behaviour and harmful drinking) and higher depression remission. Considering adolescent protective factors, weak evidence was observed of associations of moodâresilience with adolescent peerârelationship quality (β = â0.20, 95%CI:â0.36, â0.04); friendship quality (β = â0.14, 95%CI:â0.31, 0.02); risk adjustment (β = â0.16, 95%CI:â0.34, 0.03) and dysfunctional attitudes (β = 0.18, 95%CI:0.01, 0.35). There was weak evidence of behaviouralâresilience association with parent positive expressed emotion (β = â0.15, 95%CI:â0.31, 0.02) and offspring exercise (β = â0.37, 95%CI:â0.77, 0.03). No adolescent protective factors showed an association with anxietyâresilience. For sustained good MH, there was weak evidence of an association with inhibitory control (OR = 0.39, 95%CI:0.14, 1.07). Strong evidence was observed for associations between young adultâreported peer relationship quality and moodâresilience (β = â0.35, 95%CI:â0.53, â0.17), behaviouralâresilience (β = â0.33, 95%CI:â0.51, â0.14) and anxietyâresilience (β = â0.34, 95%CI:â0.53, â0.14), while weak evidence was observed of an association of social activities with anxietyâresilience (β = â0.51, 95%CI:â0.97, â0.06).ConclusionsWe found limited evidence for the longâlasting effects of adolescent protective factors on adult MH resilience. Social factors remained protective into young adulthood, while family factors did not. Early preventative intervention might not be sufficient to maintain good longâterm MH, and young people will likely require more prolonged support.