Cannabis Consumption Has A Greater Impact On The Adolescent Brain Than Alcohol, Suggests New Research

Smoking too much weed might be worse for the adolescent brain than drinking, according to a new study.

The study out of the University of Montreal that looked at the drinking and smoking habits of nearly 4,000 teens around Montreal found that increased cannabis consumption has greater affects than that of alcohol. In particular, increased cannabis use seems to harm things like recall memory, perceptual reasoning, inhibition, and working memory to a greater degree than drinking.

"Over and above the effect of being prone to cannabis use during adolescence, when increases in cannabis use frequency were observed in a given year, reductions in delayed recall memory and perceptual reasoning were observed in that same year, and these effects were independent of any changes in alcohol quantity and frequency," the authors wrote.

The group of students were given a self evaluation each year for four years on how much cannabis and alcohol they were consuming. They also performed a variety of tests to measure the impact that recreational cannabis use had on their cognitive function. Falling in line with other research, students who reported use of either cannabis or alcohol were more likely to under perform in the test in comparison to their sober peers. However, as cannabis and alcohol use increased, the heaviest cannabis users began to show the worst results.

However, these results contradict a study published by researchers at the University of Colorado-Boulder earlier this year. The UCB study found that alcohol had a detrimental effect on the grey and white matter of the brain. Cannabis did not. So the findings from the University of Montreal study might only apply to the developing brain, which is exactly why legalization advocates want to regulate the market for cannabis to keep it away from adolescents. 

Ultimately, the inconsistency of the results suggests more research still needs to be done before we fully understand how cannabis impacts the brain.


Ever since recreational cannabis was legalized for adult consumption across Canada in mid-October the industry has been struggling to meet demand. And that's not going to change anytime soon, according to Prime Minister Justin Trudeau. In a recent interview, Trudeau admitted that the chronic cannabis supply shortages have been the biggest challenge the newly legalized industry has been facing.