Childhood poverty and mental health disorders in early adulthood: evidence from a Brazilian cohort study

Background: We examined the association between childhood poverty and mental health disorders (MHD) in childhood and early adulthood. We also investigated whether the association between poverty in childhood and MHD is mediated by exposure to stressful life events (SLE).

Methods: We used data from a prospective community cohort of young people assessed at baseline (M = 9.7 years, SD = 1.9), first (M = 13.5 years, SD = 1.9), and second (M = 18.2 years, SD = 2.0) follow-ups (N = 1,590) in Brazil. Poverty was assessed using a standardized classification. Exposure to 20 different SLE was measured using the Life History instrument. Psychiatric diagnoses were evaluated using the Development and Well-Being Assessment. Latent growth models investigated the association between poverty at baseline and the growth of any MHD, externalizing, and internalizing disorders. Mediation models evaluated whether the association between childhood poverty and MHD in early adulthood was mediated by exposure to SLE.

Results: Poverty affected 11.4% of the sample at baseline and was associated with an increased propensity for presenting externalizing disorders in adolescence or early adulthood (standardized estimate = 0.27, p = 0.016). This association was not significant for any disorder or internalizing disorders. Childhood poverty increased the likelihood of externalizing disorders in early adulthood through higher exposure to SLE (OR = 1.07, 95 CI% 1.01-1.14). Results were only replicated among females in stratified analyses.

Conclusions: Childhood poverty had detrimental consequences on externalizing MHD in adolescence, especially among females. Poverty and SLE are preventable risk factors that need to be tackled to reduce the burden of externalizing disorders in young people.