Study Finds Lower Blood Flow to Brain in Marijuana Users
"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," said Dr. George Perry, editor in chief of the Journal of Alzheimer's Disease.
A new, large-scale study published in the Journal of Alzheimer's Disease finds there is abnormally low blood flow in virtually every area of the brain studies in current and former marijuana users that in healthy controls, including areas known to be affected by Alzheimer's pathology, such as the hippocampus. The news of this study comes as several U.S. states' voters approved recreational or medicinal use of marijuana in November 2016 voting.
The paper is based on a brain imaging study by researchers using single photon emission computed tomography (SPECT), a type of imaging that evaluates blood flow and activity patterns. Their data set included 26,268 patients who came for evaluation of complex, treatment-resistant issues to outpatient neuropsychiatric clinics in several states between 1995 and 2015. Of those people, 982 current or former marijuana users had brain SPECT at rest and during a mental concentration task compared to almost 100 healthy controls.
A co-author of the study, Dr. Elisabeth Jorandby, M.D., said, "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. Our research has proven that marijuana users have lower cerebral blood flow than non-users. Second, the most predictive region separating these two groups is low blood flow in the hippocampus on concentration brain SPECT imaging. 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."
"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," said Dr. George Perry, editor in chief of the journal.
Another co-author, Dr. Daniel Amen, M.D., founder of Amen Clinics in Costa Mesa, Calif., said the research "demonstrates that marijuana can have significant negative effects on brain function. The media has given the general impression that marijuana is a safe recreational drug; this research directly challenges that notion. In another new study just released, researchers showed that marijuana use tripled the risk of psychosis. Caution is clearly in order."