The Pharmacogenetic Study , Readiness to Change, and Pharmacological Intervention for Smoking Cessation in Schizophrenia

Specific Aims Accordingly, this proposal aims at testing the following major hypotheses: 1\. Nicotine patch therapy and bupropion are effective in smoke cessation among motivated psychiatric outpatients with schizophrenia. 1a. High dose nicotine patch therapy is significantly more effective in inducing smoke cessation than regular dose nicotine patch therapy. 1b. Nicotine patch therapy and bupropion are more effective in inducing smoke cessation in those treated with "atypical" neuroleptics as compared to those treated with "typical" neuroleptics. 2\. Response to nicotine patch therapy is associated with genetic polymorphisms of DRD2, dopamine transporter (DAT; SLC6A3), CYP2A6 and CYP2D6 genes. 3\. Smoke cessation is associated with a significant decrease in the activity of CYP1A2, as well as a significant increase in the steady-state concentration of the neuroleptics received by the patients. This will lead to an increased incidence of treatment emergent side effects, which may be controlled by neuroleptic dose adjustment. 4\. patients in the stage of preparation or contemplation (stronger readiness to quit smoking) are more likely to reduce smoking and stop smoking than those in the stage of precontemplation (weaker readiness to quitting smoking).