Genetic correlates of self-harm hospitalization: Insights from polygenic scores in the Taiwan Biobank

Understanding the genetic underpinnings of self-harm can reveal its etiology and guide preventive efforts. Although multiple psychiatric and anthropometric traits are associated with the risk of self-harm, their shared polygenic architecture remains unclear. We investigated the association between psychiatric and anthropometric traits and self-harm hospitalization using the polygenic score (PGS) approach in East Asian populations. A mediation analysis was conducted to quantify how these traits mediate the genetic predisposition to self-harm.

We included 111,899 unrelated participants with genotyping data from the Taiwan Biobank linked to the National Health Insurance Research Database for diagnoses defined by the International Classification of Diseases (ICD) codes. Logistic regression was used to assess the association between these traits, PGS, and the risk of self-harm. Mediation analyses were performed to explore the potential mediating role of these traits on the relationships between their PGS and self-harm.

PGSs for smoking (odds ratio [OR] per SD in the PGS = 1.35), major depressive disorder (MDD; OR = 1.25), and substance use disorder (SUD; OR = 1.19) were associated with an increased risk of self-harm hospitalization. Mediation analyses indicated that 14.49 %, 20.50 %, and 4.91 % of the observed associations between the PGSs for smoking, MDD, and SUD, respectively, and self-harm hospitalization were mediated through the corresponding traits.

Suicidal and non-suicidal self-harm were not differentiated. ICD-based self-harm identification may lead to potential misclassification and missed cases.

Our findings contribute to understanding the genetic architecture of self-harm hospitalization in East Asian populations.