Internalizing and externalizing problems in childhood and adolescence as predictors of work incapacity in young adulthood

There is limited information regarding the association between youth mental health problems and work incapacity in adulthood. We investigated whether internalizing (depressive, anxious, somatic complaints) and externalizing (aggressive, rule-breaking) behavior problems in childhood and adolescence were associated with sickness absence (SA) and disability pension (DP) in young adulthood. Data were used from the population-based and prospective Twin Study of Child and Adolescent Development (TCHAD) which includes all Swedish twins born in 1985-1986 (N = 2570). Internalizing and externalizing behavior problems were assessed with the Child Behavior Checklist at ages of 8-9, 13-14, 16-17, and 19-20 years. Individuals participating in TCHAD were followed regarding SA and DP during 2001-2013 using nationwide registers. Cox regression models were applied to assess hazard ratios (HR) with 95% confidence intervals (CI). Each one-unit increase of rule-breaking behavior implied a significant higher risk for SA in early adulthood, despite of age at assessment, with the highest HR of 1.12 (95% CI 1.05-1.19) at age of 8-9 years. Higher levels of anxious and depressive symptoms in childhood and adolescence were associated with DP in early adulthood despite age at assessment, with the highest risk at age 19-20 years [HR 1.31 (95% CI 1.12-1.53)]. The associations attenuated slightly when familial factors were taken into account. Internalizing and externalizing behavior problems identified at an early age (8-9 years) increased risk for SA and DP in young adulthood. These findings indicate that early prevention and intervention efforts to reduce behavior problems may promote a successful start in working life.