Risperidone Long-acting Versus Oral Risperidone in Patients With Schizophrenia and Alcohol Use Disorder

Comorbid alcohol/substance use disorder (SUD) in people with schizophrenia is a major concern, both in view of the high frequency of SUD among patients with schizophrenia and the difficulty in managing such patients. Though antipsychotic medications are effective in reducing symptoms and impairment in persons with schizophrenia, the typical antipsychotic agents are of limited value in controlling alcohol/substance use in these patients. Extrapyramidal, dysphoric side effects of conventional neuroleptics may actually promote the use of substances in an attempt to counteract these effects. In addition, medication non-compliance is common among patients with schizophrenia. Novel antipsychotics have altered treatment expectations and outcomes for patients with severe forms of schizophrenia. A growing number of studies have assessed the effects of oral risperidone in persons with dual disorders. Potential mechanisms of action by which risperidone and other atypical antipsychotics could decrease substance use include being less likely to cause extrapyramidal side effects than typical agents, improving negative symptoms and ameliorating a dysfunction of the brain reward system. Risperidone long-acting injectable medication addresses issues of noncompliance, while avoiding peak blood levels of oral preparations, thereby minimizing EPS and improving negative symptoms of schizophrenia. Risperidone may also facilitate dopamine neurotransmission in the prefrontal cortex and correct a hypothesized dysfunction of the brain reward system. This study is an open, randomized, controlled study to compare intramuscular long-acting risperidone to oral risperidone with blinded ratings to determine whether the long-acting form of risperidone has greater efficacy in reducing substance use. Patients with schizophrenia or schizoaffective disorder, age 18 to 65, who are taking any single oral antipsychotic medication except clozapine or risperidone long-acting may be enrolled.