Marijuana May Offset Alcohol-Induced Cognitive Impairment Among Teens

San Diego, CA: Compounds in cannabis may offset some of the adverse effects of alcohol on the adolescent brain, according to clinical trial data published online by The Journal of Studies on Alcohol and Drugs.

Investigators at the University of California at San Diego assessed the cognitive performance of 130 adolescents (65 with histories of heavy marijuana use, and 65 non-marijuana-using controls), ranging in age from 15.7 to 19.1 years. Authors reported that the use of marijuana appeared to moderate the adverse effects of alcohol on verbal learning and memory.

Researchers determined, “Regression models revealed that greater alcohol hangover symptoms predicted worse verbal learning and memory scores for non-marijuana users, but alcohol hangover symptoms were not linked to performance among marijuana users.”

They concluded: “Results confirm previous studies linking adolescent heavy drinking to reduced verbal learning and memory performance. However, this relationship is not seen in adolescents with similar levels of alcohol involvement who also are heavy users of marijuana.”

A previous study published in 2009 reported that binge drinkers who also used cannabis experienced significantly less white matter damage to the brain as compared to subjects who consumed alcohol alone.

“Binge drinkers who also use marijuana did not show as consistent a divergence from non-users as did the binge drink-only group,” investigators concluded. “[It is] possible that marijuana may have some neuroprotective properties in mitigating alcohol-related oxidative stress or excitotoxic cell death.”

Commenting on the findings, NORML Deputy Director Paul Armentano said, “Alcohol and cannabis appear to have contrasting effects on the human brain,” he said. “Ethanol is clearly toxic to healthy and developing cells whereas moderate doses of cannabinoids appear to be relatively non-toxic and possibly even neuroprotective.”

For more information, please contact Paul Armentano, NORML Deputy Director, at: Full text of the study, “Learning and memory performances in adolescent users of alcohol and marijuana: interactive effects,” appears in The Journal of Studies on Alcohol and Drugs.