Casual pot use causes brain abnormalities in the young: study
By Alex Dobuzinskis | Reuters, 4/16/2014
(Reuters) - Young, casual marijuana smokers experience potentially harmful changes to their brains, with the drug altering regions of the mind related to motivation and emotion, researchers found.
The study to be published on Wednesday in the Journal of Neuroscience differs from many other pot-related research projects that are focused on chronic, heavy users of cannabis.
The collaborative effort between Northwestern University's medical school, Massachusetts General Hospital and Harvard Medical School showed a direct correlation between the number of times users smoked and abnormalities in the brain. .....click "Read More" below to continue.....
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"What we're seeing is changes in people who are 18 to 25 in core brain regions that you never, ever want to fool around with," said co-senior study author Dr. Hans Beiter, professor of psychiatry and behavioral sciences at Northwestern University.
In particular, the study identified changes to the nucleus accumbens and the nucleus amygdala, regions of the brain that are key to regulating emotion and motivation, in marijuana users who smoke between one and seven joints a week.
The researchers found changes to the volume, shape and density of those brain regions. But more studies are needed to determine how those changes may have long-term consequences and whether they can be fixed with abstinence, Beiter said.
"Our hypothesis from this early work is that these changes may be an early sign of what later becomes amotivation, where people aren't focused on their goals," he said.
The study, which was funded in part by the National Institute on Drug Abuse and the White House Office of National Drug Control Policy, comes as access to pot is expanding following 2012 votes in Washington state and Colorado to legalize its recreational use. The drug remains illegal under federal law.
Medical pot is allowed in 20 U.S. states.
Pot legalization advocates make the argument that marijuana is safer than alcohol a central part of their campaigns.
Other research has found drinking alcohol alters the brain, Beiter said. But while researchers do not know exactly how the mental rewiring seen in pot users affects their lives, the study shows it physically changes the brain in ways that differ from drinking, he said.
This latest study fits with other research showing marijuana use has significant effects on young people because their brains are still developing, and Beiter said he has become convinced that marijuana should only be used by people under 30 if they need it to manage pain from a terminal illness.
(Reporting by Alex Dobuzinskis; Editing by Ken Wills)
https://ca.news.yahoo.com/casual-pot-causes-brain-abnormalities-young-study-020709104--finance.html
16.4.14
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When this study was released in 2014, it was widely reported as showing that casual cannabis use causes brain damage.
ReplyDeleteSome media organizations conveniently left out a few details of the study. For one the 'abnormalities ' they found in the cannabis users were two areas of the brain with greater size and neural density. This usually is not a bad thing. The authors also never claimed that cannabis caused this, "Because this is a cross-sectional study, causation cannot be determined...", or that it is 'damage'. Also, the cannabis group (only 20 subjects) used much more alcohol and used more tobacco than the control group. They were in no way "casual users", as the authors claimed, using an average of 11 joints per week. No meaningful conclusions either way can be drawn from this poorly designed study.
The Northwestern/Harvard study was criticized just days after release in the same journal:
http://www.jneurosci.org/content/34/16/5529/reply#content-block
There is much other criticism:
http://liorpachter.wordpress.com/2014/04/17/does-researching-casual-marijuana-use-cause-brain-abnormalities/
After observing how the media misinterpreted the findings, study author Jodi Gilman stated:
"The conclusions were modest in the paper — we never say marijuana causes these changes. The media may have given that impression in headlines, but the study doesn't show causation."
"The main point is there are differences in the brains of these two groups. The subtlety is we don't know if those differences are causal and relate to function or behavior"
"Since this paper has come out, some people think I'm a crazy conservative against legalization," she says. "I don't think anyone should go to jail for using marijuana — people can do what they want — I just want them to know what's happening to the brain."
A followup study discovered that cannabis is not associated with structural changes in the brain. The previously found associations were likely due to confounding variables such as alcohol use:
"Groups were matched on a critical confounding variable, alcohol use, to a far greater degree than in previously published studies."
"In sum, the results indicate that, when carefully controlling for alcohol use, gender, age, and other variables, there is no association between marijuana use and standard volumetric or shape measurements of subcortical structures. "
Weiland et al. Daily Marijuana Use Is Not Associated with Brain Morphometric Measures in Adolescents or Adults. The Journal of Neuroscience. 2015.
http://www.jneurosci.org/content/35/4/1505.abstract
If we are going to discuss popular substances which have an adverse effect on the brain, it would make much more sense to talk about alcohol, which has been proven to cause permanent brain damage in teens and adults. Cannabis on the other hand, despite decades of study has not been shown to cause permanent brain damage in adult users. In fact, the U.S. government has a patent on the cannabinoids found in cannabis for protecting the brain:
"This new found property makes cannabinoids useful in the treatment and prophylaxis of wide variety of oxidation associated diseases, such as ischemic, age-related, inflammatory and autoimmune diseases. The cannabinoids are found to have particular application as neuroprotectants, for example in limiting neurological damage following ischemic insults, such as stroke and trauma, or in the treatment of neurodegenerative diseases, such as Alzheimer's disease, Parkinson's disease and HIV dementia."
Patent 6630507 - Cannabinoids as antioxidants and neuroprotectants. Filing date: Apr 21, 1999.
Now that alcohol was found to be the culprit in the Northwestern study should we prohibit it?