Clinical determinants of hospital treated deliberate self‐harm repetition: A time to recurrent event analysis

INTRODUCTION: Psychiatric disorders are strongly associated with hospital treated deliberate self‐harm (DSH). However, the effect of specific disorders on risk for DSH repetition in sex‐age‐subgroups is understudied. The present study aims to assess the influence of various specific psychiatric disorders on risk for subsequent DSH repetition by way of time to recurrent event analysis on a national cohort of DSH patients. MATERIAL AND METHODS: Individuals aged 18 and older presenting to somatic hospital for DSH during the period 2008–2018 was identified through national registers. A parametric shared frailty survival analysis was used to investigate the impact of various psychiatric disorders on risk of DSH repetition. RESULTS: The cohort consisted of 39,508 individuals of which 8634 (21.8%) presented with 24,028 repeated episodes of hospital treated DSH. Borderline personality disorder increased the risk of DSH repetition in females (adjusted HR 1.49, CI 1.41–1.57), while alcohol use disorder (HR 1.12, CI 1.04–1.19) and substance use disorders (adjusted HR 1.22, CI 1.14–1.32) increased the risk of repetition in males. The strongest impact of psychiatric disorder on risk of repetition was found among the elderly. Previous history of DSH was associated with the highest increased risk of repetition. CONCLUSION: Prior history of DSH was strongly associated with DSH repetition, but the influence of psychiatric disorder varied significantly by specific diagnoses and by sex and age of the patients. Efforts to prevent DSH repetition should be age and gender specific and designed to meet the needs of people with different specific psychiatric disorders.