Childhood household dysfunction and risk of self-harm: A cohort study of 107 518 young adults in Stockholm County

Abstract

Background: Childhood household dysfunction (CHD) is a risk indicator for self- harm in young adulthood. However, less is known about the effects of cumulative exposure to CHD and the role of school performance and childhood psychopathology in the relationship. Methods: We used a Swedish cohort of 107 518 individuals born in 1987-91. Register-based CHD indicators included familial death, parental substance abuse and psychiatric morbidity, parental somatic disease, parental criminality, parental separation/single-parent household, public assistance receipt and residential instability. Estimates of risk of self-harm from age 15 [measured as registered diagnosis of self-harm according to the International Classification of Disease (ICD)] were calculated as hazard ratios (HR) with 95% confidence intervals (CIs). Results: CHD indicators, with exceptions of familial death and parental somatic disease, were associated with an increased risk of self-harm. Accumulating CHD indicators increased the risk of self-harm in a graded manner, and individuals exposed to five or more indicators had a f5-fold risk [hazard ratio (HR): 4.9, 95% CI 3.8-6.4) after adjustment for school performance, childhood psychopathology and confounders. Exposure to five or more CHD indicators and poor school performance conferred a 20-fold increased risk, compared with non-exposed individuals in the highest grade group. The risk was elevated by 9-fold for those with five or more CHD indicators and a history of childhood psychopathology. Conclusion: Childhood household dysfunction is associated with the risk of self-harm in young adults, particularly when accumulated. The risk is markedly increased in the subgroup of disadvantaged children that fail in school or develop childhood psychopathology.