Decision-Making Signatures of Methamphetamine and Alcohol Use Disorders.

Background: Aberrant decision-making is a hallmark of substance use disorders (SUDs), often impeding recovery. While uncertainty, comprising risk and ambiguity, is central to real-world choices, its distinct effects in SUDs remain underexplored. This study disentangles risk and ambiguity to identify context-specific impairments in methamphetamine (MUD) and alcohol use disorders (AUD).

Methods: We used a Choice under Risk and Ambiguity (CRA) task to examine uncertainty decision-making (UDM) in 101 individuals with MUD, 56 with AUD, and their respective healthy control groups (HCs; n = 45 and n = 75). Group-level analyses applied a modified psychometric function to estimate decision parameters, while individual-level UDM indicators were derived using custom computational methods and subjective value models.

Results: Individuals with MUD exhibited heightened reward sensitivity and a stronger preference for large rewards under high uncertainty, with flexible shifts across ambiguity levels. Besides, reward sensitivity under high ambiguity was linked to symptom severity. In contrast, individuals with AUD showed no evident decision-making impairments across conditions and, like HCs, adopted conservative strategies under ambiguity. Direct comparisons confirmed more pronounced UDM impairments in MUD than in AUD.

Conclusion: These findings underscore the heterogeneity of decision-making patterns across SUDs, validating the need for precision in therapeutic strategies.