Examining the effects of varenicline and naltrexone on delay discounting among individuals with alcohol use disorder

AIMS: Individuals with alcohol use disorder (AUD) often exhibit heightened delay discounting, a behavioral marker associated with poor treatment outcomes. Medications such as naltrexone and varenicline influence reward-related decision-making, but their effects on delay discounting remain unclear. This study examined whether these medications influence delay discounting rates. METHODS: We conducted a double-blind, randomized, placebo-controlled trial in 34 treatment-seeking adults with AUD. Participants were assigned to naltrexone (50 mg/day), varenicline (2 mg/day), or placebo and completed a two-week medication titration followed by a six-day quit attempt. Delay discounting was assessed at baseline and post-treatment using the Monetary Choice Questionnaire (MCQ). General linear models tested medication effects on post-treatment discounting, controlling for baseline discounting, education, and income. RESULTS: A significant interaction between medication and baseline delay discounting emerged (P = .03; η2 = .67). Among participants with lower baseline discounting, naltrexone reduced delay discounting compared to placebo and varenicline. However, no significant effects were observed in participants with higher baseline discounting. Varenicline did not significantly alter delay discounting compared to placebo. CONCLUSIONS: These findings suggest that naltrexone may reduce delay discounting in individuals with AUD, but primarily among those with lower discounting rates. The results highlight the importance of baseline traits in understanding medication effects on decision-making. Given the small sample size, future research should replicate these findings in larger trials and explore whether delay discounting could serve as a biomarker for personalized AUD treatment.