Time to rehospitalization of clozapine versus risperidone in the naturalistic treatment of comorbid alcohol use disorder and schizophrenia

Clozapine is known to be effective in treating schizophrenia patients with comorbid alcohol use disorders (AUD). However, few prospective studies have examined the effect of clozapine on community survival of the patient, which is one of the most important indicators of success for patients with schizophrenia. In this prospective, naturalistic, observational, community-survival-analysis study, we compared the effect of clozapine and risperidone on two-year psychiatric hospitalization rate and time to hospitalization in the treatment of patients with schizophrenia and comorbid AUD. We found that the clozapine treated patients were readmitted to hospital significantly later (mean survival = 526.5 days, n = 25 patients) than the risperidone treated patients (mean survival = 420.4 days, n = 36 patients). The survival curve for the clozapine-treated patients was significantly different from that of the risperidone treated patients (log-rank test, df = 1, p = .045). At the end of the two-year study period, 75% of the risperidone treated patients had been admitted to the hospital, compared to only 48% of the clozapine treated patients. These findings suggest that clozapine should be considered for the treatment of schizophrenia patients with comorbid AUD. However, due to the limitations of this study, further studies will be required to confirm these findings.