Could Marijuana Use Increase Vulnerability to Alzheimer's?

A new study warns that smoking pot reduces blood flow in every area of the brain – especially in the right hippocampus, an area that is affected by Alzheimer's disease.

Key Notes

  • Amen Clinics researchers studied nearly 1,000 brain SPECT scans from marijuana users and compared them to a group of healthy, non-marijuana users
  • Marijuana users have lower blood flow all over the brain
  • Users had significantly reduced blood flow in the right hippocampus
  • Hippocampus is essential to getting memories into long-term storage
  • It is one of the first regions of the brain affected by Alzheimer's disease

As the legal pot industry booms in America, the research team at Amen Clinics and I have conducted a new, large scale brain imaging study that gives reason for caution.

Published in the Journal of Alzheimer's Disease, our study utilized single photon emission computed tomography (SPECT), a sophisticated brain imaging study that evaluates blood flow and activity patterns, and showed abnormally low blood flow in marijuana users brains, compared with healthy controls.

Our scans show that the brains of cannabis users had abnormally low blood flow in virtually every part of the brain studied, and the most drastically reduced area of blood flow was in the hippocampus — suggesting serious vulnerability to Alzheimer’s.

Low blood flow in the brain is the number one predictor of Alzheimer’s disease!

Our research demonstrates that marijuana can have significant negative effects on brain function.

The media gives the general impression that marijuana is a safe recreational drug. This research directly challenges that notion.

Caution is clearly in order.

Our researchers analyzed data from a broad database including 26,268 patients across the US between 1995 and 2015.

“As a physician who routinely sees marijuana users, what struck me was not only the global reduction in blood flow in the marijuana users brains, but that the hippocampus was the most affected region due to its role in memory and Alzheimer’s disease,” according to researcher Elisabeth Jorandby, M.D., one of the co-authors on the study.

Our research demonstrates that marijuana users have lower cerebral blood flow than non-users.

“This work suggests that marijuana use has damaging influences in the brain – particularly regions important in memory and learning and known to be affected by Alzheimer’s.”

Dr. George Perry, Editor in Chief of the Journal of Alzheimer’s Disease said,

“Open use of marijuana, through legalization, will reveal the wide range of marijuana's benefits and threats to human health. This study indicates troubling effects on the hippocampus that may be the harbingers of brain damage.”

It’s important to take our team’s findings as a word of caution before we see marijuana as harmless. More research is needed.


Check out the Amen Clinics blog at

This post was published on the now-closed HuffPost Contributor platform. Contributors control their own work and posted freely to our site. If you need to flag this entry as abusive, send us an email.