NORML Responds To Latest Media Frenzy Over Pot and ‘Brain Damage’ Fears

The mainstream media launched into a reefer mad frenzy this week after researchers from Harvard University in Boston and Northwestern University in Chicago published the results of a neuroimaging study assessing the brains of a small cohort of regular marijuana smokers and non-users. The brain scans identified various differences between the two groups in three aspects of brain morphometry: gray matter density, volume, and shape. These differences triggered dozens of high-profile media outlets to lose their collective minds. Here’s a sampling:

CNN: Casual marijuana use may damage your brain

Financial Post: Study proves occasional marijuana use is mind altering

Time: Recreational pot use harmful to young people’s brains

International Business Times: Casual Marijuana Smoking at Young Age May Cause Irreparable Brain Damage – Even at One Joint Per Week

UK Telegraph: Smoking cannabis will change you. That’s not a ‘risk’, it’s a certainty

Yet despite the sensationalist headlines, the study itself was hardly newsworthy. Decades of research pertaining to the potential residual adverse effects of cannabis on brain cognition have failed to support the notion that marijuana poses any sort of permanent brain deficits. And as I write today on, this study similarly failed to report any sort of real-world adverse consequences associated with cannabis use:

Why the Media’s Fear-Mongering on Marijuana Effects on the Brain Is Faulty

[excerpt] Using high–resolution MRI imaging, scientists identified specific changes in particular regions of the brain that they inferred were likely due to marijuana exposure. (Since researchers only performed a single MRI session, they could not say definitively whether these changes were, in fact, caused by cannabis or whether they existed prior to subjects’ use of the plant.) Notably, however, these changes did not appear to be associated with any overt adverse effects in subjects’ actual cognition or behavior. (Separate studies assessing youth use of legal intoxicants, such as nicotine and alcohol, have also been associated with documented changes in brain structure. Ditto for caffeine intake in preclinical models. These findings have received far less media attention.)

Both the cases (20 marijuana users) and controls (20 nonusers) in the study were recruited from local universities, undermining the notion that the alleged ‘brain damaged potheads’ were any more academically challenged than their non-using peers. Further, as summarized by HealthDay: “Psychiatric interviews revealed that the pot smokers did not meet criteria for drug dependence. For example, marijuana use did not interfere with their studies, work or other activities, and they had not needed to increase the amount they used to get the same high.”

In other words, case subjects and controls appeared to function similarly in their professional and academic endeavors.

You can read the full text of my response here.

[Update: I have a separate op/ed (“Smoke weed, turn into a pothead? Not so fast”) responding to this paper online in The Los Angeles Times here.]

Fortunately, my critique of this latest paper — and in particular the mainstream media’s sensationalist and erroneous coverage of its findings — is far from the only one. Below are links to several other excellent analyses:

MedPage Today: Striking a Nerve: Bungling the Cannabis Story

Daily Beast: No, Weed Won’t Rot Your Brain

Bits of DNA (blog): Does researching casual marijuana use cause brain abnormalities?

DPA Blog: Does Smoking Dope Really Make You a Dope?

33 thoughts

  1. Good work Paul!
    What else do prohibitionists have left but more lies and propoganda? Didnt their mother ever tell them not to lie or they’d have to keep lying to keep from getting busted?
    Well guess what Michelle Leonhart, David Koch and Kevin Sabet: You’re busted.
    While its distressing to see CNN on this report of marijuana madness and weed propoganda (in anticipation of a Weed 3 trilogy before elections over patent “507,”) There’s a major disconnect between prohibitionist-funded media propoganda and WHERE younger, mota-vated American voters are getting their news. Young people are getting their news on line, more often from non for profits like NORML, or from entertainment news like the Daily Show whose role is to portray the hypocrisy and trivial irony of paid media propoganda.
    2/3 of Americans could get out and vote this November, just because of marijuana ballots in their state. That’s huge. It will be a national record. Thats more people than voted during Obama’s first election, which was roughly half the U.S.
    Now more than half the U.S. Is poised to have some form of medicinal or decriminalization legislation passing this November, passing the tipping point of prohibition.
    We see through the propoganda. We know that some guy who ate a marijuana brownie and jumped off a balcony to his death in Colorado had other issues. America is laughing at the paid off media right now. We are smiling because we know that a bully cries like this when they finally know the fear of their own extinction.

  2. After taking several IQ tests over the Internet then calculating an average, my IQ measured EXACTLY what it was in Kingergarden 58 years ago. I can NEVER corroborate these studies with my own experience.

    Long ago I learned NEVER to believe these studies.

  3. Yeah the media has been pathetic. First it will cause you to jump out of windows if you eat it, then your brain is going to change, and now if you eat marijuana you will kill your wife because you are hallucinating so bad.

    This is exactly reefer madness.

    The media acts like people have had legal access to marijuana for the first time ever this year. Seemingly ignorant to the fact many states have had medical marijuana for a long time and recreation marijuana has been legal for over two years.

    Give us a break.

  4. Know what is worse than smoking pot as a kid? Going to jail for smoking pot as a kid.

    So if the argument for marijuana prohibition is that it causes brain damage, than why don’t we try and outlaw alcohol again like we did so many years ago.

    I call bull shit on this studdy. Just keep pushing the oxycodone as the cure all pain medication for medical patients and wonder why we have such a big heroin problem. One day our politicians will stop listening to big Pharm. and start listening to the people they work for.

  5. Oh, know what else causes brain damage in kids?

    Dravet syndrome, also known as Severe Myoclonic Epilepsy of Infancy (SMEI).

  6. I also want to add that I’ve read through this report, and adding the fact that in a medical professional. I utilized marijuanas stress relieving properties often during my academic career and it only ever helped me deal with the many difficult trials my degree out me through. I also want to share that what they found is not indicative of anything negative, despite media hyping it as such. Increased dendritic growth in the brain as well as increased grey matter are generally associated with an increase in neuropathways. This has been a known association with the plants use for decades, and is neither anything new, nor a negative consequence. Infact, for the most part, it can be considered a healthy byproduct of the plants usage. Increased neuropathways are often associated with greater mental cognition later in life when cognition usually begins to fall apart via the onset of dementia and other as of yet fully understood maladies of an aging brain. increased neurogenesis is also considered to be associated with a pseudo protective measure against the onset of Alzheimer’s.

    As such, it is pretty obvious that the media is sensationalizing (often with obvious anti-legalization biased agendas) in an attempt to bank ratings off the rising legalization changes in the nation. Or in short, “fear mongering sells”.

  7. Here it comes the 2014 version of Reefer Madness and the drama is getting funnier as 420 approach. Call that a study by using only 40 people to prove their point?

  8. Galileo, the studies do show that marijuana usage is generally safe. The government data shows marijuana is safe. Why don’t you “believe in them”???

    The fucking retards that read these studies and choose to interpret scientific data in their own prejudiced ways are what we shouldn’t believe in.

  9. Thank God for NORML!

    It amazes me how many seemingly trustworthy news sources are so ready to pounce on anything that makes marijuana look bad while ignoring the overwhelming evidence that it is not…

  10. Thanks your for all that you do…..

    We need more positive publicity. like billboards , and tv air time, and news paper adds , that promote cannabis in a manner that is positive………

    SO again , Thank you NORML for all that you do…..

    As always
    thanks for reading

  11. Thesis, Antithesis, Synthesis.

    We always knew there would be blowback as legalization gained significant ground. And so quasi-scientific “studies” are presented as evidence even if at times flimsy. And prohibitionists eat this stuff up and are quick to also present it as “the scientific community has spoken”. Really? Because the scientific community has been presenting evidence of medicinal qualities for quite some time now as well. If one is going to embrace science to back up their argument, then I feel I should point out that the positive evidence far outweighs the negative. The days of the Cheech n’ Chong profile is slowly becoming myth, (I’m happy to say) and real world Cannabis consumers are starting to present a whole different cross section of of society. And not a moment too soon either.
    There’s still ways to go yet, but I think we just might be at the juicy part of the learning curve and might even get a little bit ahead of it in the next few years. Upward and onward.

  12. My grandfathers brother was an MD in 1920-1930’s in Colorado.
    He delivered both of my parents. Typically he would have given cannabis to both of my grandmothers to ease labor pain. My parents also were likely given cannabis tinctures for croup,etc. These children of the 1920-1930’s grew up in spite of their brain damaged childhood and we now call them the Greatest Generation. Interesting. It would seem the Emperor Media-Science has no clothes.

  13. I figured out about a dozen years ago that I was at least as bright as anyone else. Boy was I pissed, when I went to the adult education program in 2006 and took my TAB before entering math, and english classes I was rated as having the education level of a 5th grader. I’ve earned a GED, a high school diploma, and am now enrolled in a college technical program. So should I act real smart in an attempt to impress everyone? Got me in trouble, hey I I’m not saying I’m a genius, or should I act real dumb, with a big stupid looking smile on my face, and drool running down my chin; ha ha people who know you’re a pot head will believe the act expect less of you, and you can get away with more. How about acting like my normal irreverent self? One things for sure, I don’t want to be like THEM, rude, self-serving, full of dirty tricks, half-truths, and lies. When it comes to someone like my brother, or Idaho congressman Chuck Winder, I’ve found that the old saying ( if you don’t have anything good to don’t say anything at all.) works well. Such is my moral dilemma, and besides quietness has a power all its own you go through your day watching people hop by with one foot in their mouths, and your anger grows. I am the Voice of the Resistance,and out of my quiet anger you are my voice, those of you on this web-page, those who marched in the occupy wall street, and other protests these last few years, Leap, and the Norml women’s alliance, even the guy I saw down at the store yesterday with his green stay calm hit a bong t-shirt you are my voice 420, four f@##$ing twenty, and Fleetwood Mack forever.

  14. Thank You NORML, keep up the good work, you will always be in my prayers, Removal of cannabis from the schedule is the only way to release the hounds of truth.

  15. What we have hear is a failure to communicate. Some Departments of our government we just cant reach. So they want to hold the patent to cannabinoids as neuroprotectants and sell off the rights? Since 2001, someone in the Department of Health and Human Service wants it this way and he or she Gets it! Hypocrisy! At the same time the same Department will take your children away if you so much as admit to smoking weed.
    Meanwhile the Department of Justice Declares war on America, because the “controlled substance” turns out to be ourselves.

    We dont need your civil war; And that means YOU; GW Pharm, GlaxoSmithKline, Pfizer, Koch Industries, (who bought DuPont’s timber and Petrochemical patents in 2004), DuPont’s piss testing empire, Kraft synthetic foods, Altria (owners of Philip Morris, Starbucks and %50 of the domestic tobacco industry), and oh yeah, the Drug-Prison-Military-Industrial Complex.
    Just to name a few of the evil empires…

    Seems to me that if any rational person wants brain damage they should read the Constitution then read the C.S.Act then read their Congressman’s response to their rational questions.
    Don’t worry, marijuana can cure you after talking to a Congressman too. (sigh, gotta keep trying, right NORML?) Isn’t marijuana an incredible plant?

  16. When gorilla fighters want to over through a government the first thing they do is take over the countries radio and television stations. Today in AMERICA one does not need gorilla fighters to capture the communications all that needs to happen is rich tycoons buy the networks and uses them as a cheering squad for his or her political party. I was told in school that my country had truthful news agencies that did not deal in propaganda. Our tycoon owned networks HELP POLITICAL LIES GET LEGS. Pot is still being lied about by our leaders.

  17. I’m all for legalization and nothing has motivated me more for legalization than the long history of lies and hysteria regarding cannabis. Prohibition has only made things worse. People should be able to freely grow, harvest, and consume their own drugs. But when it comes to selling drugs, I do think there need to be regulations and controls. People should know exactly what they are getting when they buy a drug. I say this because my first edible was a cookie. Half the cookie produced no results. 3 hours later I ate the other half. After a night of hell I found out that the little 10X on the package meant 10 dosages. I never knew. It wasn’t clear. And just maybe the cannabis was all on one side of the cookie? In any case, while pot is far less harmful than alcohol, it can still be dangerous. I’d like to see more regulation of alcohol and I’d like to see sensible regulation of cannabis. And no more lies and bullshit!

  18. Thank you NORML
    First let me say that i’m a 48yr old. Second when I was in high school up unti my jr. Year I was failing my grades were D’s and E’s. During the summer of at the end of my jr year I was introduced to cannabis guess what? I had more focus and I applied my self during that final year and I graduated with my class. It took a ell of lot of work and it wasn’t pretty but I did it. Don’t smoke now and I haven’t for years the reason being I have to much to lose and I won’t take the chance even with MI. Med laws. I get sevier back cakes and just take Advil .i suffer because I will not be harassed by my state. We need to stop prohibition.

  19. As they say, when the truth rears its head amongst the waters of a sea of ignorance, it is first ridiculed; then, the supporters of said truth are attacked; and finally, when the reactionaries and stagnant members of society have finally realized that they are in error, said truth is accepted. It happened when Galileo Galilee presented a model of our solar system in which the Earth orbited the sun; it happened when Charles Darwin published his thesis On The Origins of Species; and it happened when the great physician Ignaz Semmelweis first proposed that the rinsing of hands with a chlorinated lime solution between treating patients drastically cut down on the death rate in his hospital. I praise NORML for their tireless efforts to see our archaic prohibitionist stance laid aside in favor of policy based on facts instead of fervor.

  20. Hey galileo there’s a lot of holes in your logic. First off, Internet IQ tests are crap. Second off, ones IQ can naturally change up to 20 points in somebody’s lifetime. Third off, one of the points in this article was that there were too few participants in this study. Your comment was self assessing anecdotal evidence. Fourth off, IQ tests don’t exactly test intelligence. The test is a predictor of ones ability to perform in school. It started in France when school became mandatory and they needed to assess where to stick school aged kids going to school for the first time. Fifth off, there is a pretty big margin of error on those tests to begin with (6 or 12 point, can’t remember) Sixth off, different intelligence tests test different things.

    The study seems flawed but to discount it based on taking online tests and comparing them to kindergarten results half a century in the past is asinine. Everyone has different preferences on what they do when they get high. How are we to know that you don’t get high and read the dictionary?

  21. There are more defeciets to the study, because as stated in the study itself (in the discussion part), the user group had a significant higher alcohol consume than the control group, the user group was not screened for previous use of other drugs, and they also mentioned that early alcohol debute could not be ruled out as the cause.

  22. @Name: Excellent comment! I’m not surprised that the prohibitionists are taking positive info about MJ and trying to pretend that it’s actually negative–that dates back to the very start of the failed Drug War, when Nixon didn’t get the anti-MJ results he wanted from his paid scientific committee(who apparently had some damn principles and weren’t willing to lie just because that’s what the guy with the paycheck wanted), and just threw a hissy fit, threw the data in the trash, and started the Drug War anyway. NORML, is there any chance of getting this kind of info into a post or raising awareness that even if true, these results are not actually negative?

  23. It’s a pretty worn-out cliché, but, in regards to our pathetic mainstream media, again apropos: first they ignore you, then they ridicule you, then they fight you, then they lose. They’ve passed from the ridicule stage to the fighting stage–and they’re on the brink of losing. If we can get Oregon and Alaska this year, those yellow-bellied rat-f***ers–and I’m talking the prohibitionists and media ass wipes–will be on the run.

  24. Please, spread the word in the only way we have left that’s certain to bypass the prohibitionist media. They hope enough fear & doubt can be sown to prevent voters saying ‘Yes’ to cannabis legalization. Forward this webpage to everyone who even remotely believes in prohibition fear mongering scare tactics, a.k.a. standard operating procedure. The people who need to read this rebuttal the most are those who forward prohibition fertilizer, like the aforementioned news agencies (who outed themselves), to grow ever newer lies to keep cannabis use a crime. Maybe, it should be pointed out that every time the prohibitionists lose ground they stir up these kind of reports. Just to make people believe prohibition is somehow preferable to organized crime controlling the sale of cannabis? Organized crime (gangs) have no problem selling cannabis to minors, unlike licensed merchants who won’t, once it’s finally legal, again. Cannabis prohibition was created by lies & is maintained by lies. Thank you NORML for all your hard work spreading the truth to set all Americans free.

  25. these people ,who say they can identify areas of the brain,,that respond to cannabis are wrong…
    I too have seen MRI,,and this claim has got to be false,,,

  26. A genius once stated: first they laugh at you, next they pity and demean your efforts, then they fight you till the losses are honestly counted, then you win. Thanks Ghandi, peace

  27. What does it mean when it says audit under alcohol in the study, did they count of alcohol use. Also is says 7 of them were tobacco smoker, that could have also had an affect.

  28. 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 the association with structural changes in the brain was actually due to alcohol use, not cannabis:

    “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.

    Now that alcohol was found to be the culprit will they fight alcohol legalization?

  29. Can these people do a study on how prescription drugs is killing America now??? Oh wait! Ruining our lives on that is OK……

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