Divorce, genetic risk, and suicidal thoughts and behaviors in a sample with recurrent major depressive disorder

Background Theories of risk for suicidal thoughts and behaviors (STB) implicate both interpersonal and biological factors. Divorce/separation and aggregate genetic liability are robustly associated with STB, but have seldom been evaluated in conjunction with one another. Furthermore, whether these factors are effective predictors in high-risk populations is not clear. Methods Analyses were conducted in a sample of Han Chinese women with severe recurrent major depressive disorder (maximum N = 4380). Logistic regressions were used to evaluate the associations between divorce/separation and polygenic scores (PGS) for suicidal ideation or behavior with STB. Where appropriate, additive interactions between divorce and PGS were tested. Results Divorce/separation was significantly associated with increased risk of suicidal ideation, plans, and attempts (odds ratios = 1.28–1.61). PGS for suicidal ideation were not associated with STB, while PGS for suicidal behavior were associated with ideation and plans (odds ratios = 1.08–1.09). There were no significant interactions between divorce/separation and PGS. Conclusions Consistent with theories of suicidality, the disruption or end of an important interpersonal relationship is an indicator of risk for STB. Aggregate genetic liability for suicidal behavior more modestly contributes to risk, but does not exacerbate the negative impact of divorce. Thus, even within a high-risk sample, interpersonal and biological exposures distinguish between those who do and do not experience STB, and could motivate targeted screening. Further research is necessary to evaluate whether and how the context of divorce contributes to variation in its effect on STB risk.