Background: There are two reasons to believe antidepressants and anxiolytics might help in smoking. First, anxiety and depression are symptoms of nicotine withdrawal, and smoking cessation sometimes precipitates depression. Second, smoking appears to be due, in part, to deficits in dopamine, serotonin and norepinephrine, all of which are increased by anxiolytics and antidepressants.
Objectives: The aim of this review is to assess the effectiveness of such drugs in aiding long term smoking cessation. The drugs include bupropion; buspirone; diazepam; doxepin; fluoxetine; imipramine; meprobamate; moclobemide; nortriptyline; tryptophan; ondansetron; venlafaxine and the beta-blockers metoprolol, oxprenolol and propanolol.
Search strategy: We searched the Cochrane Tobacco Addiction Group trials register which includes trials indexed in Medline, Embase, SciSearch and PsycLit, and meetings abstracts.
Selection criteria: We considered randomized trials comparing anxiolytic or antidepressant drugs to placebo or an alternative therapeutic control for smoking cessation. We excluded trials with less than 6 months follow-up.
Data collection and analysis: We extracted data in duplicate on the type of study population, the nature of the drug therapy, the outcome measures, method of randomisation, and completeness of follow-up. The main outcome measure was abstinence from smoking after at least six months follow-up in patients smoking at baseline. We used the most rigorous definition of abstinence for each trial, and biochemically validated rates if available. Where appropriate, we performed meta-analysis using a fixed effects model.
Main results: There was one trial each of the anxiolytics diazepam, meprobamate, metoprolol and oxprenolol. There were two trials of the anxiolytic buspirone. None of these showed evidence of effectiveness in helping smokers to quit. There was one trial each of the antidepressants fluoxetine and moclobemide, two of nortriptyline, and four trials of bupropion. Nortriptyline and bupropion increased cessation and other antidepressants might also be effective. One trial found combined bupropion and nicotine patch produced higher quit rates than patch alone.
Reviewer's conclusions: There is little evidence that anxiolytics aid smoking cessation. Some antidepressants (bupropion and nortriptyline) can aid smoking cessation. It is not clear whether these effects are specific for individual drugs, or a class effect.