Psychological mediators of bupropion sustained-release treatment for smoking cessation

Aim The study aimed to test simultaneously our understanding of the effects of bupropion sustained-release (SR) treatment on putative mediators and our understanding of determinants of post-quit abstinence, including withdrawal distress, cigarette craving, positive affect and subjective reactions to cigarettes smoked during a lapse. The specificity of bupropion SR effects was also tested in exploratory analyses. Design Data from a randomized, placebo-controlled clinical trial of bupropion SR were submitted to mediation analyses. Setting Center for Tobacco Research and Intervention, Madison, WI, USA. Participants A total of 403 adult, daily smokers without contraindications to bupropion SR use. Intervention Participants were assigned randomly to receive a 9-week course of bupropion SR or placebo pill and to receive eight brief individual counseling sessions or no counseling. Measurements Ecological momentary assessment ratings of smoking behavior and putative mediators were collected pre- and post-quit. Findings Results of structural equation and hierarchical linear models did not support the hypothesis that bupropion SR treatment improves short-term abstinence by reducing withdrawal distress or affecting the subjective effects of a lapse cigarette, but provided partial support for mediation by cigarette craving reduction and enhanced positive affect. Bupropion SR effects on point-prevalence abstinence at 1 month post-quit were also mediated partially by enhanced motivation to quit and self-efficacy. Conclusions Results provided some support for models of bupropion SR treatment and relapse and suggested that motivational processes may partially account for bupropion SR efficacy.