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 person‐years, 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.