Long Term Liability if Cannabis Rots Our Brains

This is your brain on drugs. Let it go...
This is your brain on drugs. Let it go…

It all starts with correlation. In 1950, the British Medical Journal published an article showing a high correlation between lung cancer and smoking tobacco. In 1998, the tobacco industry entered a settlement agreement with the attorneys general of 46 states, agreeing to change its marketing tactics, to abandon certain industry groups, and to pay out more than $206 billion.

Fast forward to a couple of days ago, when the journal Psychological Medicine published an article showing an alleged correlation between patients smoking high-potency cannabis and damage to the white matter connections in their brains. A group of researchers from King’s College in London studied 56 individuals with first-episode psychosis and 43 individuals without any history of psychosis. The researchers took brain MRIs of the subjects and had them answer questions about their past illicit drug use, including their use of cannabis. The researchers’ primary finding was that frequent use of high-potency (meaning 16-22% THC) cannabis is “significantly associated” with altered “callosal microstructure integrity.” Basically, our body’s cannabinoid receptors are tied in with our development of white matter and gray matter in the brain, and frequent use of high-THC marijuana may cause greater than normal cell self-destruction in parts of our brains.


Correlation-based research like this is easy to attack. After the article on correlation between tobacco and lung cancer came out, the largest U.S. tobacco manufacturers came together to form the Tobacco Industry Research Committee. In 1954, the Committee published “A Frank Statement to Cigarette Smokers.” In that paper, the Committee sought to inject doubt into the nascent consensus that tobacco was bad for people. The Committee pointed out that much of the experimentation had been on mice, not people; it stated that there is no agreement between authorities that prove cigarette smoking is a cause of cancer; and it stated that statistics linking cigarette smoking with cancer could apply to any number of other possible causes. The statement was using one of the most tried and true methods of attacking early-stage scientific research — correlation does not equal causation. Showing that two events are correlated does not prove that one causes the other. Proof of causation requires a randomized controlled experiment, which would be very hard to do and probably unethical if it meant the experimental group would likely get cancer or brain damage as a result.

And so the tobacco industry was in a 40+ year war against science until it eventually crumbled. These industry vs. science battles happen all the time. The NFL has been fighting on brain damage to players. The oil and coal industries have been fighting on climate change.

So, where does that leave cannabis? Let’s assume that this research is valid and there is indeed a long-term negative effect on the brains of frequent users of high-THC marijuana. The cannabis industry is in a very different place than other industries that have faced these issues. It is more diffuse. The Master Settlement Agreement on tobacco was entered into by four large tobacco companies. We just don’t have that ownership concentration in the marijuana industry. The industry has not really coalesced yet regarding industry/lobbying groups. Some advocacy organizations are working on it, but even they would admit there’s a lot of work left before any specific group could claim to speak for the industry.

This lack of group cohesion may actually be helpful to the cannabis industry in this specific instance. The urge to put out something along the lines of the “Frank Statement” would be hard to resist, especially for those that really believe that the research showing long-term health effects of marijuana use are flawed. But that impulse to fight back against the early science is what doomed the tobacco industry. Tobacco companies spent thirty years telling the public tobacco was safe. So when they tried to change their defense to one of contributory negligence/risk assumption (“why should we pay money when our users knew all along or at least should have known all along that tobacco was dangerous?”), courts and the public saw through it. We weren’t going to let them off easy after they had perpetrated a fraud on the public for 30+ years.

So my advice to the cannabis industry is to let science run its course. Don’t look at every negative study as an attack, and don’t seek to discredit legitimate research. If subsequent research shows marijuana is safer than some of the early research suggests, great. If it shows the opposite, then communicate openly and honestly with your customers, and allow them to choose what risks to take. One of the reasons the alcohol industry hasn’t faced the same type of lawsuits as the tobacco industry is because it hasn’t played nearly as much of a role in denying science. Its arguments for risk assumption are much stronger as a result. Cannabis companies need to pay attention, so that they don’t repeat tobacco companies’ mistakes.

7 responses to “Long Term Liability if Cannabis Rots Our Brains”

  1. the only companies that are repeating the tobacco mistakes are the pharma companies that release a new drug , hide the bad effects from the fda, then pay settlements and lawsuits 5 years later when its revealed that the new drug causes heart attacks.

    as to this specific study? i’d actually welcome rat brain study. just feed the rats cannabis and smoke them out, even put it in the water. let the rats live as long as possible, with controls. then after they die of natural causes , take em apart and compare the brains.

    we all want accurate research. please no more propaganda though?

  2. I agree with the message of this article in principle and in general, but I think that it’s inappropriately applied in this specific case. Psychosis Studies at King’s College London are not investigating possible harms in good faith, but have committed scientific fraud. The problems with their work go way beyond correlation vs causation, for example, ignoring the reasons why their subjects say that they use cannabis, and ignoring the relevance of core symptoms in the disorders they study to the effects of cannabis. Furthermore, the differences they found are very small, and cannot be accurately described as evidence of damage. In the studies of tobacco, the evidence of harm was very substantial, but here it’s absent. A 2% difference in one brain region is nothing to get worked up about; such differences probably exist between people who prefer green olives over black olives, just as they probably exist between people who prefer bud over hash. But reporting such tiny differences in a correlational study as damage, while ignoring the reasons their subjects actually told them for their preferences, is outrageous and should be condemned by the scientific community, not just by people invested in the specific topic of marijuana’s brain effects.

    That said, yes, legitimate research should run its course. For example, I eagerly await the results examining the relationship between marijuana use and vascular events (ie, stroke and stroke-like events). It’s important that this be studied carefully. But some questions just shouldn’t be on the table anymore, such as “if cannabis rots our brains.” Enough studies have failed to find any such effect that we can conclude it’s not happening, and so why have patience for people continuing to report it as if the results of the studies had come back with damning evidence, instead of showing no difference or almost no difference? We should be studying the real effects of marijuana, not dwelling on things we now know perfectly well that it doesn’t do

  3. So despite all the evidence of brain rot, you think your clients can avoid liability for brain rot because they didn’t deny it? If they don’t deny the studies in the New England Journal of Medicine, why are they selling an inherently dangerous product? Strict liability applies in that circumstance, and in there is nothing that requires suits only against a limited number of defendants. Everyone involved in manufacturing and selling this harmful product is liable, particularly to the developing adolescents and twenty-somethings who are most susceptible to this rot — and whose lives will be forever changed by your clients’ callous disregard for civic accountability.

    • Do you make similar comments on articles about the oil and gas industry? The plastics industry? Coors? Coca-Cola? Gun manufacturers?

      How about the medical industry? Since about 400,000 people die every day due to medical mistakes, maybe you should direct your ire in that direction. Maybe you could save a life.

      Who is responsible for adolescents? Wouldn’t that be the parents? Maybe the legal age of an adult should be changed to… 30 years old?

  4. Medical science is frequently publishing papers about studies with a small number of people, then making the leap that the results apply to everyone. Then the media makes bold statements with flashy headlines about the research, but both the media and science rarely follow up to see if the results were duplicated in a larger group. (You know, if causation can actually be proven.)

    And because of the brain’s plasticity, if one area shows a reduction (is it really damage?), that probably means that other areas see increases in synaptic activity.

    “Let’s assume that this research is valid and there is indeed a long-term negative effect on the brains of frequent users of high-THC marijuana.”

    There are many (many) things that cause long-term damage and negative effects on the brain, like chronic pain, sugar, depression, abuse, and aspirin. We can’t talk about any long-term negative effects from THC without also talking about the benefits. The only real question — as with any drug — is whether the benefits outweigh the harms. I believe the research already proves that, and to claim otherwise is just plain hypocrisy.

    I’d like to see the research community prove that the benefits outweigh the harms when it comes to alcohol.

  5. Before jumping on any bandwagon, one would hope this research could be repeatable. The fact the sampling size was only 50 people would never be accepted in any peer reviewed journal. One would hope that a research university like King’s College could find more than 50 subjects to participate in this test.

    However, upon further examination of the report and more importantly the sponsor behind the report, we find that Glaxo Smith Klein is actually in partnership with King’s College and just sponsored a big initiative around brain research.

    GSK is one of the biggest supporters of anti-legalization laws. It is in the company’s best interest to discredit cannabis. It is in the best interest of the college to please their supporters and partners. Kings College faculty are connected to many large corporations, quite a few of them in the pharmaceutical industry.

    The study only included 50 subjects. If they had sampled 500 subjects, different story.

    I would like to see news organizations question these “research reports” from corporate sponsored university research facilities.

  6. I am a Cannabis user and have for 35 years now ,Being a quadraplegic since 1983 ,I have used it for pain,spams and just because I like it.I wish for a place I can donate ME after I do die Just to prove to the Lies Cannabis isnt anything like the manmade Pharm drugs ..It really does do good,I quit using Prescription drug Baclafin 13 months ago now,went in for my yearly checkup and What my doctor told me was a BIG suprise,,He said I have no reason to make any changes in anything I do, He said I am Healthier now than I was 2 years ago:::Ive been useing cannabis everyday now going on 2 years–and will not stop till I DIE,either from it or some dumbass on a rampage –peace all and smoke on,,Danny J Westlet

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