Alcohol Was Always the More Dangerous Drug

Researchers at the University of Colorado Boulder ran brain scans on 853 adults and 439 adolescents to compare what alcohol and cannabis actually do to the brain over time. The findings, published in the journal Addiction, landed more or less where many people suspected but few had confirmed: alcohol reduces the volume of both white and gray matter; cannabis does not meaningfully alter brain structure.

Gray matter governs brain function. White matter handles communication between nerves. Alcohol shrinks both. Cannabis, in the amounts studied, leaves them largely alone. Co-author Kent Hutchison told Medical News Today that while marijuana can carry some negative consequences, they’re definitively not as pronounced as the negatives from alcohol.

Hutchison noted an irony built into decades of neuroscience: researchers have known for years that alcohol is bad for the brain. Studies on cannabis, meanwhile, kept contradicting each other—one finding hippocampal shrinkage, the next pointing to cerebellar changes, the next finding nothing unusual at all. This study tried to settle the comparison by examining both substances side by side with a large enough sample to actually mean something.

I’m not surprised by the finding. I’m a little surprised it took this long to study rigorously. The social and legal framework around both substances has always had more to do with politics and historical accident than pharmacology. Cannabis was criminalized through a combination of racism, industrial lobbying, and moral panic, while alcohol sailed through the same era because the temperance experiment had already failed spectacularly. The brain never got a vote.

None of this means smoking heavily is consequence-free. Long-term effects—particularly on adolescent brains, and on memory and motivation over time—remain incompletely understood. But if you prefer a joint to a round of shots, the science is at minimum on your side. The hangovers certainly were already.