A randomized controlled trial of a behavioral economic supplement to brief motivational interventions for college drinking

Abstract

Objective: Behavioral economic theory suggests that a reduction in substance use is most likely when there is an increase in rewarding substance-free activities. The goal of this randomized controlled clinical trial was to evaluate the incremental efficacy of a novel behavioral economic supplement (Substance-Free Activity Session [SFAS]) to a standard alcohol brief motivational interviewing (BMI) session for heavy-drinking college students.

Method: Participants were 82 first-year college students (50% female; 81.7% White/European American; M age = 18.5 years, SD = 0.71) who reported 2 or more past-month heavy drinking episodes. After completing a baseline assessment and an individual alcohol-focused BMI, participants were randomized to either the SFAS or to a Relaxation Training (RT) control session. The SFAS was delivered in an MI style and attempted to increase the salience of delayed academic and career rewards and the patterns of behavior leading to those rewards.

Results: The combination of an alcohol BMI plus the SFAS was associated with significantly greater reductions in alcohol problems compared with an alcohol BMI plus RT at the 1-month and 6-month follow-up assessments (p = .015, ηp² = .07), an effect that was partially mediated by increases in protective behavioral strategies. BMI + SFAS was also associated with greater reductions in heavy drinking among participants who at baseline reported low levels of substance-free reinforcement or symptoms of depression.

Conclusion: These results are consistent with behavioral economic theory and suggest that a single session focused on increasing engagement in alternatives to drinking can enhance the effects of brief alcohol interventions.

(PsycINFO Database Record (c) 2012 APA, all rights reserved).

Figures

Figure 1

Flow chart illustrating recruitment, intervention assignment, and follow-up assessment.

Figure 2

Changes in past-month number of alcohol problems from baseline to follow-up by intervention condition. Error bars reflect +/− 1 standard error of the mean.

Figure 3

The upper panel shows estimated heavy drinking reductions by condition at the one-month follow-up for students with high (+ 1 SD) versus low (− 1 SD) levels of substance-free reinforcement. Students with low substance-free reinforcement assigned to the SFAS reported significantly less heavy drinking at the one-month follow-up. The lower panel shows estimated heavy drinking reductions by condition for students with high (+ 1 SD) versus low (− 1 SD) levels of depression at the six-month follow-up. Students with elevated depression assigned to the SFAS reported significantly less heavy drinking at the six-month follow-up. Participants reported an average of 6.01 (SD = 4.13) heavy drinking episodes at baseline and there were no significant differences as a function of substance-free reinforcement or depression level.