Use of Pharmacotherapy to Reduce Cue-Responsiveness in Smokers

Condition(s) targeted: Nicotine Dependence; Tobacco Dependence

Intervention: Bupropion SR (Drug)

Phase: Phase 1

Status: Completed

Sponsored by: Centre for Addiction and Mental Health

Official(s) and/or principal investigator(s):
Peter Selby, MD, Principal Investigator, Affiliation: Centre for Addiction and Mental Health

In this study we, the investigators at the Centre for Addiction and Mental Health, intend to explore whether bupropion is able to reduce smokers' responses to cigarette-related environmental cues, and craving. Previous studies have indicated that bupropion may be able to achieve these outcomes. Therefore, we predict that smokers treated with bupropion for several weeks will show reduced reactivity to cigarette cues and craving.

Official title: Pharmacotherapy-Assisted Extinction (Pharmacoextinction): A Novel Approach to the Treatment of Nicotine Dependence in Humans

Study design: Interventional, Educational/Counseling/Training, Randomized, Double-Blind, Placebo Control, Parallel Assignment, Pharmacodynamics Study

Primary outcome:

Cue-responsiveness at pre, post, and during treatment

Craving at pre, post, and during treatment

Secondary outcome:

Attentional bias at pre and post treatment

Breath carbon monoxide levels at pre, post, and during treatment

Plasma cotinine levels at pre and post treatment

Puff topography measures at pre, post, and during treatment

Detailed description: Current smoking cessation pharmacotherapy paradigms ignore the over-learned behaviour associated with smoking, thus contributing to the relatively poor absolute efficacy of pharmacotherapy. Chronic nicotine use causes adaptive changes in the brain that differ from the acute effects leading to craving when smoking is stopped. This is a key element of relapse. Thus, the development of more effective treatments involves a better understanding of craving and relapse by exploring the interaction between the psychology and neurobiology of nicotine addiction. Bupropion, an amphetamine derivative, has demonstrated efficacy in smoking cessation in motivated smokers. Its’ mechanism of action is unclear but may be mediated by extinction processes. We hypothesize that bupropion will reduce cue-responsiveness and subsequent cravings in current smokers who are not consciously attempting to quit or cut down on smoking. Fifty smokers (>10 cigarettes/day) of either sex will be recruited to take either oral placebo or bupropion 150 mg twice daily for a total of 42 days. Subjects will attend bi-weekly experimental sessions where cue-responsiveness will be measured using physiological and subjective responses to a variety of neutral and smoking-related cues. Subjective effects will be measured using the Questionnaire of Smoking Urges, the Tobacco Craving Questionnaire and Visual Analog Scales. Subjects will record smoking behaviour and subjective experiences daily in a smoking diary. Outcome variables include cue responsiveness, daily diary ratings, exhaled end tidal CO levels, plasma cotinine levels, and subjective effects. Gender effects will be assessed by using sex as a covariate in the analysis. This study will provide preliminary data on pharmacotherapy-assisted extinction as a novel approach to smoking cessation.

Minimum age: 19 Years. Gender(s): Both.

Criteria:

Inclusion Criteria:

- Males or females

- At least 19 years of age

- Smoking at least 10 cigarettes per day for at least 2 years

- Never treated with bupropion/Zyban

Exclusion Criteria:

- Co-morbid psychiatric disorder

- History of psychotic disorder or eating disorder

- Current alcohol or substance abuse/dependence (excluding nicotine, caffeine)

- Brain injury

- Seizure disorder

- Pregnancy, lactation, or at risk of becoming pregnant

- Current regular use of psychotropic drugs

- Known allergy or sensitivity to bupropion

Centre for Addiction and Mental Health, Toronto, Ontario M5S 2S1, Canada

Starting date: June 2005
Ending date: May 2006
Last updated: September 12, 2006