Childhood adversity and common mental disorders in young employees in Sweden : is the association affected by early adulthood occupational class?

Background: Childhood adversities are associated with an elevated risk for common mental disorders (CMDs). Whether the strength of the association also holds for young employees is unclear. Given the increase in CMD rates in young adults over the past decade, identification of risk factors has important implications for future public health interventions. The current study aimed to investigate the effects of childhood adversities on CMDs. Additionally, the role of occupational class (non-manual/manual workers) in the relationship was examined. Methods: This population-based longitudinal cohort study included 544,003 employees, 19-29 years, residing in Sweden in 2009. Adversities included parental death, parental mental and somatic disorders, parental separation or single-parent household, household public assistance and residential instability. Estimates of risk of CMDs, measured as prescription of antidepressants and/or psychiatric care with a clinical diagnosis of CMDs, between 2010 and 2016 were calculated as relative risks (RR) with 95% confidence intervals (CI), using a modified Poisson regression analysis. Occupational class (non-manual/manual workers) was explored as a potential moderator. Results: In both manual and non-manual workers, childhood adversities were associated with an elevated risk of subsequent CMDs. The risk was moderated by occupational class, i.e., especially pronounced risk was found in manual workers who had experienced cumulative adversity (adjusted RR 1.76, 95% CI 1.70-1.83) when compared to non-manual workers with no adversity. Among the adversities examined, having had a parent treated for a mental disorder, having grown up in a household living on public assistance or having experienced residential instability were the strongest predictors of CMDs. Conclusion: Our findings suggest that, among young employees, manual workers with a history of multiple childhood adversities are especially vulnerable to subsequent CMDs