Could Marijuana Use Be A Key Factor In Alzheimer’s Disease?

SAN FRANCISCO — As marijuana legalization continues to grow in the U.S. and more states discuss nixing laws and restrictions on use of the drug, an alarming study finds there might be good reason to put the breaks on easing legislation.

The study found abnormally low blood flow in the hippocampus — the portion of the brain paramount to memory and learning functions — among marijuana users, suggesting use of the drug might raise the risk of developing Alzheimer’s disease.

More than 26,000 people participated in the study, and nearly 1,000 of them were regular marijuana users. Researchers said the folks who used marijuana showed reduced blood flow in nearly all regions of the brain, but especially the hippocampus. Alzheimer’s disease attacks the hippocampus first as it grows in patients.

Published in the Journal of Alzheimer’s Disease, researchers studied participants’ brains using single photon emission computed tomography (SPECT), a sophisticated imaging study that evaluates blood flow and activity patterns.

“Prior papers have suggested that marijuana can damage the brain. What surprised [us] was how low blood flow was in the brains of our cohort – virtually every brain area had reduced blood flow on perfusion imaging in relation to marijuana use,” study co-author Dr. Cyrus Raji, of the University of California-San Francisco, tells Medical News Today.

Dr. Raji adds that frequent monitoring of patients prescribed medical marijuana by their doctors was “certainly worthy of careful consideration.”


  1. Funny but true fact: 98% of all the billion dollar Alzheimers drugs fail before being released to the public. That failure rate is indicative of a complete lack of understanding about this debilitating disease.

    Now one study has determined that marijuana use contributes to AD. The study author, in saying that the findings bear “careful consideration”, means that the link between marijuana use and Alzheimers is still quite unproven and perhaps did not bear publishing as an “outlier”..

    Clearly, when looking at the demographic patterns of who is contracting AD, the vast majority never touched MJ. A much greater percentage drink alcohol, smoked tobacco, take aspirin, eat processed food, have a certain educational level, and so forth.

    It appears the study was underwritten by Big Pharma and SPECT machine owners, then cherry picked for publication as a scare tactic.

    For those millions of successful, well-adjusted Baby Boomers who have used cannabis products for decades, and have no memory or motivational issues, this finding has little credibility.

  2. Yeah, that marijuana is dangerous stuff. . . . it must be true if the pharmaceutical companies say so. Hell,
    they’d never tell an untruth or be the perveyors of anything that might hurt or kill the consumer . . . .ah, well at least. . . . . uh. . . . . oh, never mind.

  3. The truth is, there are numerous scientific studies that show that marijuana is a neuroprotectant (i.e.- protects brain cells from damage). Google it, marijuana as a neuroprotectant….

    1. I go by the evidence of the daily marijuana smokers I have met: all of them seemed to me to have broken brains.

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