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

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.