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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.'"
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.
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:
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.
Tom Swiss | the infamous tms | my blog
You cannot wash away blood with blood
There are also some indications of health benefits of small intake, but they tend to not be conclusive.
Actually, the "health benefits" have, may have been debunked and found to be systemic failures in the studies that originally found them. To put it simply, the drinking group in every test, by necessity, does not include anyone who no longer consumes alcohol due to health concerns, while the non-drinking groups may contain such individuals. This biases the health results on the non-drinking group in a negative manner. It seems when those participants who's health is compromised to the point where they no longer consume alcohol are excluded from both groups, the health benefits are either greatly reduced or vanish entirely.
Fanatically anti-fanatical
I'm all for the science, so how can the researchers claim their observations indicate marijuana has 'significant negative effects on brain function'? They didn't study that, they studied regional cerebral blood flow. What that reduced blood flow means is a whole different topic.
Marijuana use is at an all time high, yet dementia rates are at an all time low and falling. And psychosis rates are fairly steady. I have the same issue with these studies as I do with the antivaxxer studies - where are the impacts of this observation in the population and why don't we see changes in public health line up with changes in usage?
Don't get me wrong, I'm not saying marijuana is good for you nor do I believe it is some magical cure all. I just tend to distrust and question studies on such politicized topics, especially when it makes suggestions contrary to popular observation.
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.
The original banning of cannabis was from The Marihuana Tax Act of 1937, where the government declared that any sold in the US had to have the appropriate tax stamp, and then did not print any tax stamps.
This law review from 1968 covers a lot of the early cases such as how the supreme court decided whether or not American Indians can use drugs for their ceremonies and such, as well as somewhat-related cases like regulation of LSD under the Food, Drug and Cosmetic Act. It concludes that the most likely avenue for a successful challenge would be a freedom of religion argument, but would require an established religion to have a sincerely held belief in the use of cannabis specifically (as a person claiming to use it independently of a recognized, established religion for the religious/spiritual experience lost their appeal because they were held not to have a sincere belief requiring its use).
If I have been able to see further than others, it is because I bought a pair of binoculars.
This study proves that working for a publicity-hungry quack clinic damages your ability to distinguish between association and causation.
The author http://www.amenclinics.com/sta... works for a clinic http://www.amenclinics.com/ that sells dubious treatments based on dubious SPECT diagnoses.
Quackwatch has this to say:
https://www.quackwatch.org/06R...
A Skeptical View of SPECT Scans and Dr. Daniel Amen
by Harriet Hall, M.D.
I believe it is improper to charge thousands of dollars for a test that has not been validated and may not be safe. I don't think any of Amen's research has provided clear evidence that patients who have had SPECT scans have superior clinical outcomes to adequately treated patients who have not been scanned. That's really the bottom lineâ"especially with an expensive test that involves significant radiation. At the very least, he should be describing the test as experimental.
Some of Dr. Amen's treatment suggestions also worry me. For example, he recommends: (a) uses for dietary supplements that are not supported by good evidence, (b) EMDR (a highly questionable approach), and (c) hyperbaric oxygen therapy for conditions not generally considered to warrant such therapy.
I don't doubt that many patients who visit the Amen Clinics are helped. The key question, however, is whether or not SPECT scanning is justifiable for most of them. I, personally, would not undergo the test at Dr. Amen's clinic even if it were free. In my opinion, based on current knowledge, the possibility of harm outweighs any potential benefit. Pictures showing that "this is your brain on drugs" may impress some people, but I am far more impressed by quantifiable data (such as tests of mental performance) and clinical consequences (such as improved behavior) than by nonspecific pictures of "holes" in the brain.
So this is an operation that is selling diagnoses and treatments not supported by legitimate scientific research. They wound up with thousands of SPECT scans and decided to do some data-dredging on them, a process that we know is guaranteed to produce false positives http://fivethirtyeight.com/fea... https://xkcd.com/882/ , along with any real causative association. They found an association with marijuana, and rushed to publish.
Once it was published in a journal, they made claims in the press release that weren't supported by the data:
According to Daniel Amen, M.D., Founder of Amen Clinics, "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."
Clearly false. Association is not causation.