Concomitant Δ-9-Tetrahydrocannabinol and Alcohol Use: Impact on Cognitive Function and Ingestive Behavior

Legalization of medical and recreational use of marijuana decreases cannabis disapproval and increases the prevalence of cannabis and alcohol co-use. The drug co-use may alter intake amounts and patterns of each drug. Importantly, deficits in cognitive function resulting from the co-use may perpetuate concomitant cannabis and alcohol use and lead to cognitive decline and sustaining dysfunction. This review outlines reports from epidemiological, clinical, and preclinical studies. Both human and animal studies provide evidence that Δ-9-tetrahydrocannabinol, the main active constituent in cannabis, and alcohol co-use can produce additive effects on impairing cognitive function. They also indicate that there are individual differences in how the co-use affects intake amount and pattern of each drug. Importantly, the influences of cannabis and alcohol co-use on cognitive function and ingestive behavior have implications for other drug addiction and public health and warrant rigorous investigation.