Cognitive and antismoking effects of varenicline in patients with schizophrenia or schizoaffective disorder

Varenicline has been shown to be an effective anti-smoking treatment in smokers without identified psychiatric illness, and the drug's pharmacology suggests possibilities of pro-cognitive effects. However, recent reports suggest varenicline may have the potential for important psychiatric side-effects in some people. We present the first prospective quantitative data on the effects of varenicline on cognitive function, cigarette smoking, and psychopathology in a small sample of schizophrenic patients.

Fourteen schizophrenic smokers were enrolled in an open-label study of varenicline with a pre-post design. Measures of cognitive function (RBANS, Virtual Water-Maze Task), cigarette smoking (cotinine levels, CO levels, self-reported smoking and smoking urges), and psychopathology (PANSS) were evaluated prior to and during treatment with varenicline. Data on psychopathology changes among schizophrenic smokers in another drug study, in which patients were not receiving varenicline, were used for comparison.

12 patients completed the study, and 2 patients terminated in the first two weeks of active varenicline because of complaints of nausea or shaking. Varenicline produced significant improvements in some cognitive test scores, primarily associated with verbal learning and memory, but not in scores on visual-spatial learning or memory, or attention. Varenicline significantly decreased all indices of smoking, but did not produce complete smoking abstinence in most patients. During treatment with varenicline there were no significant increases in psychopathology scores and no patient developed signs of clinical depression or suicidal ideation.

Our small prospective study suggests that treatment with varenicline appears to have some beneficial cognitive effects which need to be confirmed in larger studies with additional neuropsychological tests. Varenicline appears to have some anti-smoking efficacy in schizophrenia but longer studies are needed to determine whether it will produce rates of smoking abstinence similar to those found in control smokers. Treatment with varenicline may not increase psychopathology or depression in most patients with schizophrenia, but we cannot accurately estimate the absolute risk of a potentially rare side-effect from this small sample.