Study: Frequent Cannabis Use Unrelated To Brain Morphology

Marijuana researchThe frequent use of cannabis is not associated with changes in brain structure, according to data published online ahead of print in the journal Addiction.

An international team of scientists from Australia, the United Kingdom, and the United States assessed the relationship between habitual cannabis exposure and grey matter volumes in seven regions of the brain – including the thalamus, hippocampus, amygdala, and the nucleus accumbens – in two large population-based twin samples.

Researchers reported, “[N]ormal variation in cannabis use is statistically unrelated to individual differences in brain morphology as measured by subcortical volume.”

By contrast, the repeated use of nicotine was positively associated with significantly smaller thalamus volumes in middle-aged males.

Authors concluded: “This is the largest exploratory analysis integrating brain imaging with self-report cannabis and comorbid substance use data. After correcting for multiple testing, there was no effect of cannabis use on the volume at any subcortical region of interest in young adults or middle-aged males. … In the context of expanding medicalization and decriminalization and the concerns surrounding the consequences of increased cannabis availability, our findings suggest that normal variation in cannabis use is statistically unrelated to brain morphology as measured by subcortical volumes in non-clinical samples.”

The findings are consistent with those of prior brain imaging studies reporting that cannabis exposure appears to have little to no significant adverse impact upon brain morphology — particularly when compared to the dramatic effects associated with the alcohol exposure.

The study’s findings fail to replicate those of a well-publicized 2014 paper which alleged that even casual marijuana exposure may be linked to brain abnormalities, particularly in the amygdala.

Last week, a meta-analysis of 69 separate studies reported that cannabis exposure in adolescents and young adults is not associated with any significant, residual detrimental effects on cognitive performance. The results from a pair of recently published longitudinal twin studies similarly report that cannabis use is not independently associated with any residual change in intelligence quotient or executive function.

An abstract of the study, “Testing associations between cannabis use and subcortical volumes in two large population-based samples,” appears online here.

20 thoughts

  1. You wrote “United Kingdom” twice at the beginning. The irony that this happened in an article about how Marijuana does not negatively affect the brain is killing me. LOL! Seriously though, thank you for all that y’all do! We’re still working on liberating TX. When so much that’s found online these days is part of the problem, the work that Norml is doing is part of the answer.

    1. They wrote United Kingdom and United States.
      Speaking if brain morphology.

  2. Next? Maybe assess the brain morphology changes from carbon monoxide and 4221 other Combu$tion $moking Toxins, till now widely attributed to the cannabis? Helpful findings how much money it would be necessary to spend on vapor-inhalant equipment when you can make a flexdrawtube oneheater out of a $3.95 socket wrench and less than $1.29 worth of screen, extension tube, herb sifting labor etc.?

  3. Oh, my.
    Where was all this science when The Man was trying to have me committed to the loony bin. (I know, it was, and still is, suppressed by marijuana prohibition.)

    Stunning. I have spent an entire lifetime wrestling over the most basic, rudimentary facts. No wonder the bastards have managed to drive me ccrazy, after all.

    But The Truth was always good enough for me.

  4. Thank you Paul, for your diligent, indispensible work.

    To those of us reading, I had to google “brain morphology” in order to confirm that it is as I suspected, the “study and measurement” of various parts of the brain and how they may change over time. It’s been a while since taking AP Biology in School High, but here’s what brain size relates to:

    It could be related to a tumor, or encephalitis or brain inflammations which could come and go for a variety of reasons then vanish before an autopsy as the heart stops beating. Infections, injuries and age affect brain size.

    The size of the brain does not determine one’s cognitive performance so much as our overall development which affects the number of folds in our brain, the number of synapsis or connectivity we have and the overall stimulation, homeostasis, neurogenesis and function of various parts of the brain, all of which are dynamics increased by a healthy, curious mind, regular mental, spiritual, physical and emotional excercise, a healthy diet in fresh food and regular use of whole plant cannabis.

  5. The synergy of various strains of cannabis has unlimited capacity to safely and effectively unlock our perspective potential. By CBD, THC, various terpenes and cannabinoids working together, the human mind is nourished while simulataneously being stimulated into balanced function. Part of this reason is because our industrially processed, fast food diets and materialistic lifestyles are so cannabinoid deficient the mere use of cannabis for many Americans is literally like consuming fresh vegetables after a lifetime of eating out of canned, processed food. Well sealed, dried flowers from marijuana require no artificial preservatives, very little to no pesticides, no herbicides no petrol-based fertilizers or synthetic engineering. With legally regulated quality testing we can prevent molds and poisons from infecting our marijuana. We are what we consume.

    Another reason why cognitive performance in whole plant marijuana consumers is improved without significantly affecting brain morphology is that many of the healing, brain-cell-growing properties of cannabis happen at the very small molecular level… in the way the synergy unlocks barriers in our subconscious.

    There are brain morphology studies as they relate to marijuans consumption we still need to conduct; such as how does consuming marijuana topically or orally by pregnant mothers during their first trimester prevent microcephally or spinal bifida in the developng fetus? These are two very common neurodegenerative diseases that are often exploited by Big Pharma to milk Congress for fear money, such as when they blamed the largely innocuous Zika virus for microcephaly caused by mosquito poison released into the water in Brazil. The lack of folic acud or cannabinoids in our American diets provided by fresh plants and marijuana is as apalling as marijuana is nourishing, healing and fascinating.

  6. As if by divine coincidence, just a few hours after writing the post above I was following an American tradition of cruising up a Wal Mart aisle after 10 pm watching fat people running in sweat pants, and desperate for distraction as I corralled my family to the self checkout lane I noticed Time magazine’s medical marijuana issue.

    I knew from my frequent research that Koch brothers recently bought a stake in Time so I wondered what propaganda would be found in the issue. First, most noticeably, the magazine was not promoting legal recreational markets, but mmj. There were hints of “promising medicine,” and anecdotal reporting without the hyperlinks or annotated studies of a scientific journal.

    Pages in, here came the propaganda:

    “Pregnant? Do not smoke Pot.” By Jeffrey Kluger. Second paragraph, here comes that soundbyte slander for marijuana;


    Then he takes some miniscule number from a JAMA study of “%3.9 of pregnant women” who self report using pot, which he says “may seem miniscule” but “represents a %63 increase” in marijuana use by pregnant women.

    WTF? THAT’s tabloid. NOT investigative journalism.

    Then he pulls some cheap University of Pittsburg (Koch beneficiary) study to say kids showed poor memory at age 4 due to mothers consuming marijuana when they were pregnant. He doesn’t cite a source to expain how all forms of consumption, whether “smoked” or “edibles” cause harm to the fetus.

    Then this part is so bad I have to leave it all in quotes:

    “Other risks [of marijuana consumption] include low birth weight, premature birth, anemia and anencephaly, (a condition that causes babies to be born missing section of their skull, scalp or brain). The US Centers for Disease Control and other health authorities [WHO?] warn that all of these risks apply whether the marijuana is smoked or consumed as part of an edible or candy.”

    Wow. What a crock of $#!+.

  7. Can we sue Koch Industries, Kruger, the CDC and Time magazine for bull$#!+ propaganda that screws up people’s lives?

    Even the CDC doesn’t have a link to peer reviewed studies to back up their anecdotal “Samantha tries weed” bull$#!+:

    Is this all our “Center for Disease Control” and the “World Health Organization” is good for? Lethal, blood $ucking propaganda for Koch Industries and Big Pharma?

    1. For the record, I did not purchase the Time magazine: I took pics for my comments out of a Wal Mart.

      I wont even buy Angel Soft or Quilted Northern Koch products to wipe my @$$ with. Boycott hemp and marijuana prohibitionists Koch products:

    2. The CDC says the use of marijuana by pregnant mothers “may” cause all kinds of horrors for mother and baby. That is blatantly misleading.

      Then, they advise mothers not to use it. That is where they openly expose their latent prohibitionist agenda.

      If I said to you, “You might be abducted by an alien,” that is a true statement, because I said “might,” which technically accounts for the astronomically low odds of such an event occurring.

      But if I said “Therefore, you shouldn’t ever leave the house,” then I would have crossed the line from being a scientist and a scholar, to a lunatic.

      Empirical observation tells us: our hospitals and morgues are NOT filled with marijuana casualties, of any kind.

      1. Dain,
        It’s amazing how effective propaganda is. Which is why NORML Deputy Director Paul Armentano dedicates the lion’s share of his time fighting it with citations in publications.

        I try to remain optimistic that a majority of voting Americans won’t be swayed by this trash, but then my mom just bought me a copy of Time Magazine for my birthday because she thought I would enjoy the medical marijuana topic… (hand slap to face) …and my clients can’t focus on the task at hand because they’re too busy getting their Fear-Fix and False sense of pride from watching Fox & Friends.

        We’re doomed.

        Whole Plant Marijuana is an antidote to human lemming behavior. We question authority. We pull our heads out of the @$$ of the next trail horse and ask “Where are we even GOing?”

        The U.S. isn’t the first nation governent to ever prohibit marijuana. Egypt tried it two thousand years ago in order to control their slaves and call it coincidence or consequence but their government fell in tyrrany within a century of its prohibition. We could do well to learn from archeologically recorded history and peer-reviewed science, if we can still teach our children where to find it. PubMed, not Time. JAMA, not Fox & Friends or some Morning show.

        But as truth-predators like Koch brothers continue to purchase dinosaurs of investigative journalism from the printed word, convert them to propaganda and troll on the ethernet of cyber-publications with their “think tanks” and University briberies we must continue to hold all publications and institutions accountable, as the “peer review” to truth requires our collectively engaged participation. And that begins by asking “Who are we running away from?”

      2. Having the leisure to read more of the recent Time magazine on mmj, since despite my cry to boycott all things Koch, my mother bought me the issue… I found the article on “A Grassroots movement” By Ginny Graves, where Paul Armentano is cited frequently.

        I guess this is the part of the magazine where shares of Koch didn’t venture. But despite a 1996 pic of the late greats, Jack Herrer and Dennis Peron, the theme was still about medical, not recreational marijuana. At least Paul got to quote Pubmed!

        We live in an age where every major syndicated news source takes light and dark money. The NY Times reports well on mj one day, then they promote some horrible propaganda on the next. Time magazine had good articles mixed with bad. It’s a way to legitimize horrible, unscientific propaganda, but it inadverdantly gets the good word out to people who aren’t researchers.
        To that I say we should all check our sources and investigate for ourselves. Because ultimately, no matter what we subscribe to or purchase, we are going to have to write the good laws of our future ourselves.

    3. I have a friend who happens to be a pediatrician. A couple of years ago, I was ranting about reefer madness, and the horror stories about marijuana use while pregnant, when I suddenly remembered who I was talking to! I stopped ranting, and I asked her point blank: “Are you seeing babies born ‘addicted’ to marijuana and ‘fighting for their lives?’ These kinds of problems?”

      She hesitated, and then shook her head and said quietly “No. So far as we know… nothing.”

      1. And, I briefly met a biologist once, who told me that mothers’ milk is loaded with endo-cannabinoids.

        Which makes sense… Stimulate the appetite, and bond baby with mother.

      2. Precisely, Mark; where does the prohibition of cannabinoids stop? At the cannabinoid or the endocannabinoid? If we prohibit the food, does the life still have the right to exist? If we take the food from the mother, are we not taking the milk from the baby’s mother’s breast?

        What we are fighting for here is patented synthetic poisoning; the prohibition of whole plant cannabinoids, and the propaganda and fear mongering of what we naturally produce in our own bodies through the synergistic consumption of fresh food, i.e., whole plant cannabis.
        All food and water must be well regulated and open source.

      3. Haha… “fighting synthetic patented poisoning” etc., and fighting FOR well regulated, fairly taxed legal marijuana markets.
        Thats why I blog here, so I get it right before I send it to my Reps. Lol…

  8. Its been known for decades that marijuana is beneficial to humans. We have THC receptors.
    Reasons why the lawmakers don’t want it legal is simple. They make BIG $$$ off of sickness and disease.
    WHY give humans a totally natural way to HELP health ?
    No profit there. Live longer and healthier is just what they do not want.

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