Exposure to maternal depressive symptoms in childhood and suicide-related thoughts and attempts in Canadian youth: test of effect-modifying factors.

Purpose: To (1) determine the association between exposure to maternal depressive symptoms in childhood and offspring suicide-related thoughts (SRT) and attempts (SA) in youth and young adults and (2) identify effect measure modifiers (offspring sex, family structure, maternal perceived social support, and social cohesion) of the association in 1.
Method: A cohort was constructed by linking all cycles from the National Longitudinal Survey of Children and Youth, a Canadian nationally representative survey, from 1994 to 2009 in 16,903 subjects 0 to 25 years. Exposure to maternal-reported depressive symptoms was measured when offspring were between 0 and 10 years. Offspring self-reported incident and recurrent SRT and SA were measured between 11 and 25 years. Time-to-event models under a counting process framework were used to estimate adjusted hazard ratios (HR) and relative rates (RR) and 95% confidence intervals (CI). Effect measure modifiers were examined across adjusted stratum-specific estimates.
Results: In offspring exposed to maternal depressive symptoms, the adjusted rates of incident SRT and SA (HR: 1.67, 95% CI 1.37, 2.08; HR: 1.93, 95% CI 1.43, 2.50) and of recurrent SRT and SA (RR: 1.61, 95% CI 1.33, 1.96; RR: 1.87, 95% CI 1.40, 2.36) were significantly elevated compared to non-exposed offspring. The stratum-specific rates of incident and recurrent SRT and SA were significantly elevated in females but not in males.
Conclusions: Girls exposed to maternal depressive symptoms in childhood are a target group for childhood suicide preventive strategies. Family-based preventions, and strategies to identify and effectively treat maternal depressive episodes could be beneficial for suicide prevention in offspring.