The joint effect of mental illness and parental suicide attempt on offspring suicide attempt and death: A Danish nationwide, registry-based study using multistate modeling

Abstract

Aim: The aim of this study was to analyse the joint impact of moderate-to-severe mental illness and parental suicidal attempts on suicidal attempt and premature death.

Methods: Using the Danish, nationwide health registries, a cohort study was conducted including the birth cohorts 1983-1989. Cox regression and multistate models were used to estimate relative and absolute risks of suicide attempt and premature death.

Outcome: We included 384,569 individuals and 7,218 individuals experienced their first suicide attempt during follow-up, while 2,762 individuals died of all causes. Joined exposure to parental suicide attempt and own mental illness increased the relative risk of suicide attempt (HR 22.57) and premature death all causes (HR 3.17). The absolute risk of suicide attempt before the age of 35 years was 20 % for offspring exposed to both parental suicide attempts and own mental illness (23 % for women vs. 15 % for men), while the risk of death was 4 % (0.6 % for women vs. 7 % for men).

Conclusion: Exposure to both parental suicide attempt and own mental illness increases the relative and absolute risks of suicide attempt and premature death with considerable differences across sex. These findings are important in the clinical assessment of individuals with suicidal behavior.

Keywords: Mental illness; Pre-mature death; Risk factor; Suicide attempt; Transmission of suicidal behaviour.