Investigators affiliated with the University of York, England, recently showed that varenicline, a prescription medication used to treat nicotine addiction, is effective in aiding smoking cessation and reduction in individuals with severe mental illness such as schizophrenia, schizoaffective disorder, and bipolar disorder. The findings of this meta-analysis were reported in the journal Addiction, published by the Society for the Study of Addiction.1
Smoking prevalence among individuals with severe mental illness is approximately 3 times greater than the rate observed in the general population. It is estimated that between 40% and 88% of individuals diagnosed with schizophrenia, and between 50% and 70% of those diagnosed with bipolar disorder, are cigarette smokers. “The 2007 US National Health Interview reported a prevalence of heavy smoking (defined as those smoking more than 25 cigarettes a day) of 10.3% among those without a mental disorder, 15.1% in people with bipolar disorder and 17.8% in those with schizophrenia,” the authors wrote in their publication.
Researchers conducted a literature search, and included 8 different studies that were published after 2011 in their meta-analysis (a total of 398 eligible participants). Both blinded and un-blinded randomized controlled trials (RCTs) and quasi-randomized controlled trials that compared the effectiveness of varenicline with placebo were included. Varenicline treatment varied in duration between the studies (8-12 weeks), and 81% of the participants receiving varenicline completed the treatment (82% completed the treatment in placebo groups).
“The pooled results [4 trials, with a total of 240 participants] show that participants using varenicline were more than four times more likely to abstain from smoking at the end of the treatment than the placebo groups (RR=4.33; 95% CI=1.96-9.56, I2=0%, P=0.910),” investigators reported. Similar results were recently reported in a meta-analysis of 14 RCTs that compared the effectiveness of varenicline with placebo in smoking cessation for the general population (OR=2.88; 95% CI=2.40-3.47).2 Based on these comparative results, “The increase in the odds of quitting smoking when using varenicline, compared with placebo, is greater for people with severe mental illness than for the general population,” the authors noted.
With regard to the number of cigarettes smoked (ie, cigarettes smoked at the end of treatment minus the number of cigarettes smoked at baseline), in the varenicline group, smoking was reduced by approximately 6 more cigarettes per day compared with the reduction observed in the placebo group of participants [ie, the weighted mean difference in smoking reduction was 6.39 (95% CI=2.22-10.56)].
“There was no clear evidence that varenicline was associated with an increased risk of neuropsychiatric or other adverse events in people with severe mental illness compared with placebo,” the authors concluded.
1. Wu Q, Gilbody S, Peckham E, et al. Varenicline for smoking cessation and reduction in people with severe mental illnesses: systematic review and meta-analysis. Addiction. 2016;111(9):1554-1567.
2. Cahill K, Stevens S, Perera R, Lancaster T. Pharmacological interventions for smoking cessation: an overview and network meta-analysis. Cochrane Database Syst Rev. 2013;5:1-52.