title: Mediating mechanisms for the impact of bupropion in smoking cessation treatment.
abstract: Several studies have documented the effectiveness of bupropion for smoking cessation, yet little is known about the mechanisms by which it facilitates abstinence. In this placebo-controlled randomized trial. We examined whether bupropion's effects on cessation were mediated by changes in withdrawal and/or negative or positive affect (PA). Two hundred and fifty-one smokers received 10-week treatment with bupropion or placebo, plus behavioral counseling. Changes in affect and withdrawal symptoms from pre-quit to 1 week post quit were examined as mediating variables in structural equation models. Cotinine-verified 7-day point prevalence cessation rates at the end of treatment (8-weeks post quit date) were 48% for bupropion and 29% for placebo (P=0.001). There were significant treatment effects on withdrawal and negative affect (NA); however, only change in NA predicted cessation. In a path model, change in NA was a significant mediator of bupropion's effects on cessation. However, the proportion of variance accounted for by this mediator was small, suggesting that other unmeasured factors play an important role. Laboratory-based paradigms may be useful to identify other mediators of bupropion's effects, thereby pointing to mechanisms of effect that can be bolstered in future treatment studies.
authors.affiliation: Cancer Center and Department of Psychiatry, University of Pennsylvania Health Sciences, 3535 Market Street, Suite 4100, Philadelphia, PA 19104, USA. clerman@mail.med.upenn.edu
authors.forename: Caryn
authors.initials: C
authors.lastname: Lerman
authors.forename: David
authors.initials: D
authors.lastname: Roth
authors.forename: Vyga
authors.initials: V
authors.lastname: Kaufmann
authors.forename: Janet
authors.initials: J
authors.lastname: Audrain
authors.forename: Larry
authors.initials: L
authors.lastname: Hawk
authors.forename: Aiyi
authors.initials: A
authors.lastname: Liu
authors.forename: Ray
authors.initials: R
authors.lastname: Niaura
authors.forename: Leonard
authors.initials: L
authors.lastname: Epstein
mesh_terms: D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D016642:Bupropion / Q000627:therapeutic use*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012907:Smoking / Q000188:drug therapy* / Q000523:psychology*; D016540:Smoking Cessation / Q000523:psychology* / Q000706:statistics & numerical data; D016896:Treatment Outcome
chemical_list: D016642:Bupropion