Varenicline and Smoking Cessation in Schizophrenia

There is a strong association between smoking and schizophrenia with prevalence rates ranging from 74% to 90%, versus a national average of 30% in nonschizophrenic individuals. A number of hypotheses have been proposed to explain the relationship between high smoking rates and schizophrenia, mostly relating to self-medication primarily for the negative symptoms of schizophrenia. Smoking cessation rates among schizophrenic patients are considerably lower than for other psychiatric disorders. The negative health effects of smoking increase the morbidity and mortality in schizophrenic patients. The smoking cessation agent bupropion HCl has been tested in schizophrenics, but the results on its efficacy are inconclusive. Recent works by different laboratories have shown the safety and efficacy of varenicline, a partial alpha4beta2 and full alpha7 nicotinic acetylcholine receptor agonist, as a smoking cessation agent. However, to date, no published studies have tested the safety and efficacy of varenicline in treatment of nicotine dependence in schizophrenic patients. As varenicline appears to be a promising treatment in non-psychiatric patients, it would be beneficial to examine its effects in schizophrenic patients. The central hypothesis of this application is that treatment with varenicline will safely increase smoking abstinence rates in schizophrenic patients when compared to those receiving placebo. This central hypothesis will be tested and the objectives of this application accomplished by pursuing two Specific Aims: 1) Treatment with varenicline or bupropion HCl for a period of three months will increase smoking abstinence rates in schizophrenic patents when compared to placebo; and 2) Treatment with varenicline or bupropion HCl for a period of three months will not increase psychosis in schizophrenic patients when compared to placebo. For our General Investigational Plan, we will employ a double-blind randomized placebo controlled study to assess varenicline's safety and efficacy. It is our expectation that we will demonstrate that varenicline is safe and effective in decreasing smoking rates in schizophrenic patients without exacerbating psychotic symptoms. Such outcomes will be significant, because they will offer a new treatment for smoking cessation in this vulnerable population.