Behavioral economic analysis of withdrawal- and cue-elicited craving for tobacco: an initial investigation.

INTRODUCTION: The role of craving in nicotine dependence remains controversial and may be a function of measurement challenges. The current study used behavioral economic approach to test the hypotheses that subjective craving from acute withdrawal and exposure to tobacco cues dynamically increases the relative value of cigarettes. METHODS: Using a 2 (1-hr/12-hr deprivation) × 2 (neutral/tobacco cues) within-subjects design, 33 nicotine dependent adults completed 2 laboratory sessions. Assessment included subjective craving and behavioral economic indices of cigarette demand, namely Intensity (i.e., cigarette consumption at zero cost), O(max) (i.e., maximum total expenditure), Breakpoint (i.e., highest acceptable price for cigarettes), P(max) (i.e., price at which consumption becomes sensitive to price), and elasticity (i.e., price sensitivity). Behavioral economic indices were generated using a Cigarette Purchase Task in which participants selected between cigarettes for a subsequent 2-hr self-administration period and money. RESULTS: Main effects of deprivation and tobacco cues were present for subjective craving and multiple behavioral economic indices of cigarette demand. Interestingly, deprivation significantly increased Breakpoint (p ≤ .01) and P(max) (p ≤ .05) and had trend-level effects on Intensity and O(max) (p ≤ .10); whereas cues significantly reduced elasticity (p ≤ .01), reflecting lower sensitivity to increasing prices. Heterogeneous associations were evident among the motivational variables but with aggregations suggesting variably overlapping motivational channels. CONCLUSIONS: These findings further support a behavioral economic approach to craving and a multidimensional conception of acute motivation for addictive drugs. Methodological considerations, including potential order effects, and the need for further refinement of these findings are discussed.

Measures of abstinence in clinical trials: issues and recommendations.

A workgroup formed by the Society for Research on Nicotine and Tobacco reviewed the literature on abstinence measures used in trials of smoking cessation interventions. We recommend that trials report multiple measures of abstinence. However, at a minimum we recommend that trial: (a) report prolonged abstinence (i.e., sustained abstinence after an initial period in which smoking is not counted as a failure) as the preferred measure, plus point prevalence as a secondary measure; (b) use 7 consecutive days of smoking or smoking on > or = 1 day of 2 consecutive weeks to define treatment failure; (c) include non-cigarette tobacco use, but not nicotine medications in definitions of failure; and (d) report results from survival analysis to describe outcomes more fully. Trials of smokers willing to set a quit date should tie all follow-ups to the quit date and report 6- and/or 12-month abstinence rates. For these trials, we recommend an initial 2-week grace period for prolonged abstinence definitions; however, the period may vary, depending on the presumed mechanism of the treatment. Trials of smokers who may not be currently trying to quit should tie follow-up to the initiation of the intervention and should report a prolonged abstinence measure of > or = 6-month duration and point prevalence rates at 6- and 12-month follow-ups. The grace period for these trials will depend on the time necessary for treatment dissemination, which will vary depending on the treatment, setting, and population. Trials that use short-term follow-ups (< or = 3 months) to demonstrate possible efficacy should report a prolonged abstinence measure of > or = 4 weeks. We again recommend a 2-week grace period; however, that period can vary.