Objective: This study examines the efficacy of clonidine in smoking cessation and the influence of gender, history of major depression, and measures of nicotine dependence.
Methods: The study was designed as a 10-week double-blind randomized comparison stratified for gender and major depression. Three hundred subjects who smoked cigarettes heavily were enrolled in the study. Abstinence from smoking was evaluated by self-report and verified by serum cotinine levels.
Results: Gender, major depression recurrent type, and measures of nicotine addiction were risk factors for treatment failure. There was no clonidine effect in men, but there was a modest effect in women (odds ratio, 2.01; 95% confidence interval, 1.00 to 4.10) that was most pronounced (odds ratio, 8.5; 95% confidence interval, 1.67 to 43.62) among women with the highest risks.
Conclusion: Measures of addiction and major depression predict treatment failure. Together they are stronger predictors of outcome than drug. Clonidine is a limited aid in cessation, and drug effects come primarily from women at high risk for treatment failure. An increased risk for psychiatric complications after smoking cessation was apparent among smokers with histories of major depression, particularly bipolar disease.