Smoking and therapeutic response to clozapine in patients with schizophrenia

Background: Of patients with schizophrenia, 70 to 80% smoke. Nicotine corrects certain information processing and cognitive psychomotor deficits seen in many patients with schizophrenia. Clozapine, but not conventional antipsychotics, has been shown to correct some of these deficits. Methods: We assessed psychopathology and smoking in 70 patients with treatment refractory schizophrenia (55 smokers and 15 nonsmokers) at baseline when they were receiving conventional antipsychotics and again after they were switched to clozapine. Results: Smokers showed significantly greater therapeutic response to clozapine than nonsmokers. Smokers smoked less when treated with clozapine than when treated with conventional antipsychotics. Conclusions: Certain patients with schizophrenia have contributing pathophysiologic mechanisms that respond favorably to either nicotine or clozapine.