Occupational class and employment sector differences in common mental disorders: a longitudinal Swedish cohort study

Background: Recent increases in common mental disorders (CMDs) among young adults are of great concern although studies of CMDs in young employees are sparse. This study investigated the independent and interacting effects of sector of employment, occupational class and CMDs. Additionally, associations between type of employment branch and CMDs within each sector were examined. Methods: This population-based longitudinal cohort study included 665 138 employees, 19-29 years, residing in Sweden in 2009. Employment sector (i.e. private/public) and occupational class (non-manual/manual workers) were measured in 2009. Risk estimates of CMDs, measured as new prescription of antidepressants and/or psychiatric care with a diagnosis of CMDs, between 2010 and 2016, were calculated as hazard ratios (HRs) with 95% confidence intervals (CIs), using Cox multivariable regression analysis. Results: Public sector employees (whereof 60% manual workers) had an elevated risk for CMDs compared to private sector employees [adjusted HR: 1.14 (95% CI 1.12-1.16)]. Within each sector, manual workers were at increased risk of CMDs compared to non-manual workers. There was an interaction between sector of employment and occupational class; manual workers in the public sector had the highest CMD risk [adjusted synergy index: 1.51 (95% CI 1.29-1.76)]. The most elevated risk for CMDs was observed in those employed in health and social services and the lowest risk among construction workers. Conclusion: Sector of employment and occupational class play a role in CMDs in young employees. These findings should be taken into account in the attempts to reduce CMDs in the young working population.