Risk of self-harm in patients with body dysmorphic disorder: a population-based cohort study.

Objective: This study was conducted to determine whether individuals with body dysmorphic disorder (BDD) have an increased risk of self-harm behaviors compared with those without BDD. Methods: In this matched cohort study, we reviewed the electronic health records of all patients admitted for any reason to Hong Kong public hospitals between January 1, 1993, and December 31, 2022. We selected a cohort of 71 patients with BDD and a comparison cohort of 71 patients without BDD. Participants were followed until a diagnosis of self-harm, death from other causes, or the end of 2023, whichever occurred first. Cox proportional hazards regression models were used to assess the risk of self-harm since the onset of BDD. Results: During the 30-year study period, 2 (2.8%) individuals in the BDD group and 3 (4.2%) in the comparison group exhibited self-harm behavior. The proportion of individuals engaging in self-harm was similar between the groups (χ2 = 0.25, p = 0.62). The incidence of self-harm was 22.5 and 34.6 per 10, 000 person-years in the BDD and comparison groups, respectively. The adjusted hazard ratio for self-harm was 0.63 (95% confidence interval, 0.08-4.56) in the BDD group compared with the comparison group. Conclusions: BDD is not associated with an increased risk of self-harm. Future studies are needed to replicate our findings and further identify potential risk factors for self-harm in patients with BDD.