Relative reinforcing efficacy of cigarettes as a predictor of smoking abstinence among treatment-seeking smokers.

Abstract

Relative reinforcing efficacy (RRE) is a core feature of behavioral economic theories of addiction. A measure of RRE in smokers is the cigarette purchase task (CPT). Only one previous study has assessed whether CPT indices predict treatment outcomes among smokers with substance use disorders (SUDs) who were not motivated to quit smoking, limiting the generalizability of the results. This study was aimed at exploring demand indices as predictors of smoking abstinence among participants receiving a cognitive behavioral treatment (CBT) combined with contingency management (CM) versus CBT alone. It also sought to validate the CPT as a measure of RRE. Participants were 159 (62.3% women) smokers aged 44.8 (SD 12.6) years randomized to CBT alone or combined with CM. They smoked an average of 21.1 (SD 8.5) cigarettes per day, and their mean score on the Fagerström Test for Nicotine Dependence (FTND) was 5.5 (SD 1.9). Demand indices were generated from a hypothetical CPT assessed at baseline. Smoking levels were high (≥20 cigarettes) at prices of up to €0.10 per cigarette. Elasticity was the only index that predicted smoking abstinence at the end of treatment, but only in the CBT + CM condition. The variance explained by elasticity was 6.8% in the independent model and 4.6% in the covariate model. Cigarette demand indices and smoking-related measures were significantly associated. This is the first research showing that CPT is a valid measure of CM outcome among treatment-seeking smokers. This study also provides evidence of convergent validity for the CPT.