Risks of major mental disorders after parental death in children, adolescents, and young adults and the role of premorbid mental comorbidities: a population-based cohort study

Previous studies have shown an association between early parental death and the risk of subsequent major mental disorders (MMDs) among the bereaved children and adolescents; however, it is unclear whether this risk exists in young adults and in individuals with premorbid mental comorbidities. We aimed to explore differences between children, adolescents, and young adults in the risk of MMDs after parental death. We analyzed data from the Taiwan National Health Research Database. The index cohort was offspring (divided into four groups: aged < 6, 6–11, 12–17, and 18–29 years) whose parents had died. The control cohort was demographically matched offspring whose parents were still alive. Cox regression with adjustments for demographics was used to estimate the risk of subsequent MMDs between the index and control cohorts, including schizophrenia, bipolar disorder, and depressive disorder. We included 202,837 cases and 2,028,370 matched controls. As with the bereaved children and adolescents, the bereaved young adults had a significantly higher risk of schizophrenia (hazard ratio with 95% confidence interval: 5.63; 5.01–6.33), bipolar disorder (3.37; 2.96–3.84), and depressive disorder (2.78; 2.68–2.90) than the control cohort. The risk of MMDs was similar for maternal death and paternal death. Among premorbid mental comorbidities, bereaved individuals with premorbid substance use disorder were associated with the highest risk of schizophrenia (10.43; 8.57–12.71), bipolar disorder (12.93; 10.59–15.79), and depressive disorder (10.97; 10.22–11.78). Healthcare workers should be aware that young adults and individuals with premorbid mental comorbidities are at a higher risk of subsequent MMDs than those without premorbid mental comorbidities after parental death.