New Study Shows Marijuana Users Have Low Blood Flow To the Brain (eurekalert.org)

cold fjord writes: State level marijuana legalization efforts across the U.S. have been gaining traction driven by the folk wisdom that marijuana is both a harmless recreational drug and a useful medical treatment for many aliments. However, some cracks have appeared in that story with indications that marijuana use is associated with the development of mental disorders and the long-term blunting of the brain's reward system of dopamine levels. A new study has found that marijuana appears to have a widespread effect on blood flow in the brain. EurekAlert reports: "Published in the Journal of Alzheimer's Disease, researchers using single photon emission computed tomography (SPECT), a sophisticated imaging study that evaluates blood flow and activity patterns, demonstrated abnormally low blood flow in virtually every area of the brain studies in nearly 1,000 marijuana users compared to healthy controls, including areas known to be affected by Alzheimer's pathology such as the hippocampus. According to Daniel Amen, M.D., 'Our 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.'"

Comments

Source of information is questionable

[ebrandsberg]

The Amen clinics have been accused of using questionable techniques (https://www.quackwatch.org/06ResearchProjects/amen.html and others, just google for information on them). This isn't to say that the data isn't true, but this result hasn't been confirmed by replication of the results by other researchers or more accurate scanning methods.

selection bias and general quackery

[Mr. Slippery]

The usual Reefer Madness bad science of prohibitionists:

All data were obtained for analysis from a large multisite database, involving 26,268 patients who came for evaluation of complex, treatment resistant issues to one of nine outpatient neuropsychiatric clinics across the United States

But "people with serious neuropsychiatric people who used cannabis have low blood flow to the brain" is both less clickworthy and less politically useful than "OMG pot rots yr brain!"

And I love this: "As a physician who routinely sees marijuana users..." Yeah, that's called "a physician". Cannabis use is common, every physician has seen patients who has used it.

Both Amen and this methodology are poorly regarded. He's in the addiction treatment industry -- look at this is an old marketing pitch of his quoted in a Quackwatch article:

How your brain and soul work together determines how happy you feel, how successful you become, and how well you connect with others. The brain-soul connection is vastly more powerful than your conscious will. Will power falters when the physical functioning of the brain and the health of your soul fail to support your desires, as seen by illogical behaviors like overeating, smoking, drug and alcohol abuse, and compulsive spending.

OHOH, Officials at major psychiatric and neuroscience associations and research centers say his SPECT claims are no more than myth and poppycock, buffaloing an unsuspecting public.

Re: Here come the science deniers

[ShanghaiBill]

Since you love science so much, I'm sure you'll be willing to pay the 27.50 Euro fee to get a copy of the paper so that you can see all the details.

If you love science, you will help fight for open access to all publicly funded research. If my tax dollars paid for the research, I shouldn't have to pay again to see the results.