Educational level and the risk of mental disorders, substance use disorders and self-harm in different age-groups: A cohort study covering 1,6 million subjects in the Stockholm region.

Objective: To investigate the associations between low education and risk of mental disorders, substance use disorders and self-harm in different age-groups.

Methods: All subjects in Stockholm born between 1931 and 1990 were linked to their own or their parent's highest education in 2000 and followed-up for these disorders in health care registers 2001-2016. Subjects were stratified into four age-groups: 10-18, 19-27, 28-50, and 51-70 years. Hazard Ratios with 95% Confidence Intervals (CIs) were estimated with Cox proportional hazard models.

Results: Low education increased the risk of substance use disorders and self-harm in all age-groups. Males aged 10-18 with low education had increased risks of ADHD and conduct disorders, and females a decreased risk of anorexia, bulimia and autism. Those aged 19-27 years had increased risks of anxiety and depression, and those aged 28-50 had increased risks of all mental disorders except anorexia and bulimia in males with Hazard Ratios ranging from 1.2 (95% CIs 1.0-1.3) for bipolar disorder to 5.4 (95% CIs 5.1-5.7) for drug use disorder. Females aged 51-70 years had increased risks of schizophrenia and autism.

Conclusion: Low education is associated with risk of most mental disorders, substance use disorders and self-harm in all age-groups, but especially among those aged 28-50 years.