Concomitant clozapine reduces smoking in patients treated with risperidone.

This pilot study examines the smoking behaviors of patients treated with either risperidone alone or in combination with clozapine. Smoking behavior was evaluated using expired carbon monoxide (CO) measurements, the Fagerstrom Test for Nicotine Dependence (FTND), and a semi-structured interview. Our results indicate that patients co-prescribed clozapine with risperidone smoke significantly less than patients treated with risperidone alone (19.1+/-9.3 vs. 37.8+/-19.1 ppm CO, respectively, P=0.03). These data are consistent with previous studies showing that clozapine treatment is associated with significantly reduced smoking behavior relative to other antipsychotic agents.