Substance use disorders are common among people with a serious mental illness, with alcohol being the most frequent drug of abuse or dependence. To determine the impact of antipsychotic medication on alcohol use, a retrospective chart review was conducted among 86 patients with a co-occurring schizophrenia spectrum disorder and alcohol use disorder prescribed either a typical (first-generation) antipsychotic (e.g., chlorpromazine) or 1 of 2 atypical (second-generation) antipsychotics, olanzapine or clozapine. Data from 2 clinics were reviewed, 1 over a period of 2 years (1997–1999) and 1 over a period of 10 years (1996–2006).

• All patients showed improvement in psychiatric status regardless of medication taken.
• Patients taking olanzapine were significantly more likely to be abstinent from alcohol than those taking a typical antipsychotic (24% versus 6%).
• Patients taking olanzapine were significantly less likely to be abstinent from alcohol than those taking clozapine (24% versus 74%).
• These differences held up when results for patients with alcohol dependence and alcohol abuse were analyzed separately.

Comments by Michael Boyle, MA
If confirmed in clinical trials, clozapine could become the antipsychotic of choice for persons with schizophrenia and a co-occurring alcohol use disorder. Although clozapine can reduce white blood cell count, this risk might be offset by recent research indicating that persons receiving clozapine live longer than persons treated with any other antipsychotic, which have their own associated health risks. Second, generic clozapine is less expensive than other brand name atypical antipsychotics. Expanding this study to include costs related to alcohol use disorders, such as emergency department visits and hospitalizations, would help determine whether savings related to improved abstinence offset the cost of clozapine compared with typical antipsychotics.