Behavioral economic and value-based decision-making constructs that discriminate current heavy drinkers versus people who reduced their drinking without treatment

Objective: A substantial number of people reduce their consumption of alcohol in the absence of formal treatment; however, less is known about the mechanisms of change. The aim of this study is to explore whether constructs derived from behavioral economics and computational decision-modeling characterize the moderation of alcohol consumption that many heavy drinkers experience without treatment. Method: Case-control, pre-registered design. People who reside in the United Kingdom and who drink heavily (n = 60) or used to drink heavily but now consume alcohol in moderation (n = 60) were recruited. Participants completed self-report behavioral economic measures (alcohol demand and alcohol-related and alcohol-free reinforcement), and a two-alternative forced choice task in which they chose between two alcoholic (in one block) or two soft-drink images (in a different block). A drift-diffusion model was fitted to responses from this task to yield the underlying parameters of value-based choice. Results: Compared to heavy drinkers, moderated drinkers had significantly lower alcohol demand (Omax, p = .03, Cohen’s d = .36; elasticity, p = .03, rank-biserial correlation (rrb) = .21) and higher proportionate alcohol-free reinforcement (p < .001, Cohen’s d = .75). However, contrary to hypotheses, there were no robust between-group differences in VBDM parameters. Conclusions: Self-report behavioral economic measures demonstrate that alcohol moderation without treatment is characterized by lowered alcohol demand, and greater behavioral allocation to alcohol-free reinforcement, in line with behavioral economic theory. However, a computerized VBDM measure yielded inconclusive findings.