Quetiapine in patients with comorbid schizophrenia-spectrum and substance use disorders: an open-label trial.

ABSTRACTBackground: Preliminary evidence suggests that clozapine relieves the craving for psychoactive substances in schizophrenia patients. Quetiapine shares crucial pharmacological properties with clozapine. Promising results have been described with quetiapine therapy in patients with psychosis and substance use disorder.Methods: Based on Diagnostic and Statistical Manual of Mental Disorders – fourth edition (DSM‐IV) criteria, patients were diagnosed with comorbid schizophrenia-spectrum and substance use disorders. Patients were switched to quetiapine for a 12‐week open-label trial. Craving, quantities used, days of consumption, and severity of substance abuse were assessed every 3 weeks. Alcohol and Drug Use Scales were administered on baseline and end-point. Psychiatric symptoms, depressive symptoms, extrapyramidal symptoms, and cognition were also assessed at baseline, week 6 and week 12.Results: Twenty-four schizophrenia-spectrum patients were included in the last observation carried forward (LOCF)...