Bupropion alone and in combination with nicotine gum: Efficacy, mediation and moderation.

This randomized double-blind placebo-controlled smoking cessation treatment study was designed to assess the efficacy of bupropion alone and in combination with nicotine gum. Six hundred and eight participants were randomly assigned to receive active bupropion and active 4-mg gum (AA, n = 228), active bupropion and placebo gum (AP, n = 224), or placebo bupropion and placebo gum (PP, n = 156). Results revealed that individuals who received active bupropion, when compared to those who received placebo, were significantly more likely to be abstinent at one week, end of treatment and six months post-quit, but not at twelve months post-quit. Individuals who received active nicotine gum in combination with bupropion were more likely to be abstinent at one week than those who only received active bupropion, but there was no long-term gain from the combination pharmacotherapy. Mediation analyses revealed three significant mechanisms of action for bupropion: (1) bupropion reduced the overall withdrawal symptomatology experienced on the quit day, (2) bupropion created a more negative post-quit slope of cravings, such that individuals who received active treatment experienced reduced cravings over the first week post-quit, and (3) bupropion increased the experience of positive affect over the first week post-quit. All three of these processes resulted in a greater likelihood of abstinence at the follow-up time-points (one week, end of treatment and six months). At one week, gender moderated treatment effects such that women who received placebo medication were significantly more likely to relapse than were men or women who received active medication. There were no significant moderators of treatment effects beyond one week. (PsycINFO Database Record (c) 2016 APA, all rights reserved)