Comparative effect of antipsychotics on risk of self-harm among patients with schizophrenia

Objective: To investigate the association of different antipsychotic treatments with hospitalization due to self-harm among patients with schizophrenia. Method: This retrospective cohort study was based on Taiwan's universal health insurance database. Patients aged 15-45 years with a newly diagnosed schizophrenic disorder in 2001-2012 were included. The study outcome was the first hospitalization due to self-harm or undetermined injury after the diagnosis of schizophrenic disorders. The exposure status of antipsychotics was modeled as a time-dependent variable. The analyses were stratified by antipsychotic dosage based on defined daily dose (DDD). Results: Among 70 380 patients with a follow-up of 500 355 personyears, 2272 self-harm hospitalization episodes were identified. Compared with none or former use, current use of several second-generation antipsychotics with a dose of one DDD or above, including amisulpride, aripiprazole, clozapine, risperidone, and sulpiride, was associated with decreased risk of self-harm hospitalization, with clozapine showing the strongest effect (adjusted rate ratio = 0.26, 95% confidence interval 0.15-0.47). Conclusion: The protective effect on self-harm may vary across different antipsychotics. Further studies are needed to replicate the findings.