Decision-making impairments in binge drinking and cannabis use among young adults

The neurocognitive impairments related to binge drinking and cannabis use in youth are widespread. Decision-making abilities might also be altered but previous studies focused on a disjoint exploration of individuals with binge drinking habits and with cannabis use, and did not control for major confounding factors (e.g., comorbid psychopathological states or general cognitive level), generating contradictory results. In view of the key role played by decision-making impairments in the development of addictive disorders, sounder explorations of decision making are needed in subclinical populations.

A hundred university students divided in four groups (low drinkers, binge drinkers with no/low/high cannabis use, matched for demographic, psychopathological and cognitive abilities) performed the Iowa Gambling Task, a neuropsychological test measuring decision-making abilities under uncertainty/risk.

When compared with low drinkers, binge drinkers with no/low cannabis use did not show decision-making deficits. Conversely, when combined with high cannabis use, binge drinking was related to impaired decision making, as shown by (a) lower total scores at the Iowa Gambling Task, indicating less efficient decision making under uncertainty/risk and (b) increased entropy in the choices made throughout the task, demonstrating a lower ability to develop efficient decision-making strategies.

When controlling psychopathological states and general cognitive level, binge drinking per se is not associated with decision-making deficits. Conversely, when combined with intense cannabis use, it is related to marked decision-making impairments, which could promote the evolution toward substance use disorders. These results emphasize the importance of considering various forms of excessive substance use together when exploring their interaction with cognitive deficits in youth. We also identified the mechanisms underlying such neuropsychological deficits, paving the way for targeted interventions. (PsycInfo Database Record (c) 2026 APA, all rights reserved).