Contingency management for college student smokers: The role of drinking as a moderator and mediator of smoking abstinence during treatment.

INTRODUCTION: Contingency management (CM) is effective for promoting smoking abstinence; however, moderators and mediators of CM treatment efficacy in young adult populations are under-explored. We leveraged fine-grained data from a large randomized controlled trial: 1) to determine whether early attainment of sustained abstinence mediated the effect of treatment on abstinence; 2) to test whether heavy drinking moderated the effect of treatment on abstinence; and 3) to test a serial mediation model of the effects of drinking during early treatment on sustained smoking abstinence. METHODS: College student smokers (N=110) were randomized to receive either CM treatment or noncontingent reinforcement (NR) over a 21-day treatment period. All participants received $5 for providing twice-daily breath carbon monoxide (CO) samples. In CM, additional money was provided for samples that indicated smoking reduction (Initial Phase; first 7days), and for samples ≤5ppm (Abstinence Phase; following 14days). RESULTS: CM treatment led to greater sustained abstinence relative to NR. Longer sustained abstinence in the Initial Phase partially mediated the effect of treatment on sustained abstinence in the Abstinence Phase. Heavier pretreatment drinkers had shorter periods of sustained abstinence in the Abstinence Phase; this effect was greater in CM. A serial mediation model determined that increased drinking during the Initial Phase led to decreased sustained abstinence, which then led to decreased sustained abstinence in the Abstinence Phase. CONCLUSIONS: These data provide a greater understanding of how heavy drinking and early sustained abstinence may affect success during treatment in young adults undergoing contingency management treatment for smoking.

Contingency management and motivational enhancement: a randomized clinical trial for college student smokers.

INTRODUCTION: The efficacy of contingency-management (CM) and motivational enhancement therapy (MET) for college student smoking cessation was examined. METHODS: Nontreatment-seeking daily smokers (N = 110) were randomly assigned to 3 weeks of CM versus noncontingent reinforcement (NR) and to three individual sessions of MET versus a relaxation control in a 2 x 2 experimental design. Expired carbon monoxide (CO) samples were collected twice daily for 3 weeks. Participants earned 5 US dollars for providing each sample; additionally, those randomized to CM earned escalating monetary rewards based on CO reductions (Week 1) and smoking abstinence (Weeks 2-3). RESULTS: Compared with NR, CM resulted in significantly lower CO levels and greater total and consecutive abstinence during the intervention. Those in the CM and MET groups reported greater interest in quitting smoking posttreatment, but rates of confirmed abstinence at follow-up were very low (4% at 6-month follow-up) and did not differ by group. DISCUSSION: Findings support the short-term efficacy of CM for reducing smoking among college students. Future research should explore enhancements to CM in this population, including a longer intervention period and the recruitment of smokers who are motivated to quit.