Introduction Little is known about the effect of timing and duration of mental health problems (MHPs) on young adults’ labour market participation (LMP).

Objective This life-course study aims to examine whether and how the timing and duration of MHPs between ages 11 to 22 are associated with LMP at age 26.

Methods Data was used from Tracking Adolescents’ Individual Lives Survey (TRAILS), an ongoing Dutch prospective cohort study. Internalising and externalising problems were measured by the Youth/Adult Self-Report at ages 11, 13, 16, 19 and 22. LMP (having a paid job yes/no) was assessed at age 26. Logistic regression analyses were performed with 15-year follow-up data (N=874).

Results Internalising problems at all ages and externalising problems at ages 13, 19 and 22 were associated with an increased risk of not having a paid job (internalising problems odds ratios [ORs] ranged from 2.24, 95% confidence interval [CI] 1.02–4.90 at age 11 to OR 6.58, CI 3.14–13.80 at age 22; externalising problems ORs from 2.84, CI 1.11–7.27 at age 13 to OR 6.36, CI 2.30–17.56 at age 22). Especially young adults with a long duration of internalising problems had an increased risk of not having a paid job in young adulthood compared with participants without mental health problems (OR 3.20, CI 1.88–5.45).

Conclusion Regardless of the timing, experiencing MHPs during childhood or adolescence increases the risk of not having a paid job. In particular, those young adults with a long duration of internalising problems are at risk of not having a paid job. These findings emphasize the necessity of applying a life-course perspective when investigating the effect of MHPs on LMP. Early monitoring, mental health care, and timely provision of employment support may improve young adult’s participation in the labour market.