Study: Does Cannabis CAUSE Anxiety?
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There are two drugs that you can be sure I will always defend here on this channel: weird diet caffeinated beverages and cannabis. Today it’s gonna be the latter. Maybe tomorrow I’ll address that Panera lemonade that keeps killing people, I’m not sure yet.
“Scientists say the cannabis people are using for anxiety could be making it worse,” says Fast Company. “Heavy marijuana use may fuel anxiety disorders, new research finds. This age group is most at risk” teases Fortune Well. As a person who occasionally partakes in the devil’s lettuce and who has anxiety, these headlines definitely caught my interest. So I didn’t bother reading them and instead just hopped right on over to the Lancet to read the study these pieces were based upon: Development of an anxiety disorder following an emergency department visit due to cannabis use: a population-based cohort study.
It’s an impressive number of data points: they looked at about 35,000 people who visited an emergency room in Ontario to seek treatment after consuming cannabis. None of those people had ever been diagnosed with any anxiety disorder prior to their visit. But within three years of their ER visit, about 12% of them returned to the hospital for treatment for anxiety. That’s about 4 times the number that you’d expect in the general population, and they found that adolescent boys were at the highest risk.
Now, that IS an interesting little study. But you may notice that it does not, in fact, show that “the cannabis people are using for anxiety could be making it worse” or that “Heavy marijuana use may fuel anxiety disorders.” At all.
To start, this study did not examine heavy users. In order to qualify this study, all you had to do was not have an anxiety diagnosis and to visit the ER once for cannabis use. And that, obviously, does not suggest the patient is a frequent user – if anything, it suggests the opposite. Frequent cannabis users tend to understand that cannabis is wildly safe, especially when compared to other drugs we use frequently like alcohol and Tylenol. It’s extraordinarily difficult to die from a cannabis overdose, for instance. If you take too much, the solution is generally to drink lots of water and just…wait. You know who tends to go to the hospital after consuming too much cannabis? First time users, users who aren’t familiar with the feeling of being high, and people who ARE VERY ANXIOUS. You just need to be pretty tightly wound and to not be in the company of friends who will reassure you that you’re fine and give you a seltzer. That’s how you end up in the ER for cannabis.
For instance, a UC San Diego study published last year looked at the increasing number of elderly people who ended up in the hospital after cannabis was decriminalized in California. The lead author told reporters that as a doctor who works with the elderly, he’s seen many people who picked up edibles to help them sleep but didn’t really know how they work: “I see patients later, and they said: ‘I used a gummy, and nothing happened.’ And they don’t know much about the doses,” Han said. “So then they say: ‘I took a lot more and then, two hours later, my heart is racing — I’m so anxious I don’t know what’s going on!’ And they end up in the emergency department.”
I’ve combed through every study I can find on why, exactly, the majority of people end up in the ER after using cannabis and it seems to be accidental ingestion (for kids under 10), first time users who got freaked out like that lead author describes, and people who are actually on other drugs as well, like this study that found that nearly 50% of trauma patients in the hospital who tested positive for cannabis also tested positive for amphetamines, cocaine, opioids, or Phencyclidine. (That study had a scary finding, that those trauma patients who came in high were more likely to be placed on a ventilator, but also there was no change in mortality or ICU length, and yeah, half of them were on several drugs at once, so…less scary than I thought going in.)
So, no, anyway, this new study just does not tell us anything about the actual relationship between cannabis use and anxiety. Like pretty much every other observational study like this, they can’t show causation, in that people with anxiety might be more likely to try cannabis to treat it. And in this case they have even less convincing data than self-reports, because they can’t even say that these ER visits were due to heavy or frequent use of cannabis.
I’d like to note a few more interesting causes for concern that are related to all of this. First of all, there is a suspected link between cannabis use and schizophrenia and other types of psychosis. I know I’m not alone here, in that many people who have accidentally eaten too much of that happy brownie or took too big a hit off the bong have experienced what’s known as cannabis-induced psychosis. Sometimes when you take too much things get really trippy and sometimes you feel like you might die. In my case, as I believe I’ve mentioned before, I became unstuck in time like Billy Pilgrim and thought that I could flip through time like a book, but then I got scared that I might get re-stuck in a particular moment and never get back to the present. My boyfriend at the time put on a comforting TV show (Parks and Rec I believe) and that scared me more because I couldn’t tell if I had seen that episode before or if I was just remembering seeing it in the future. It’s funny now but let me tell you I was freaked the hell out.
But I didn’t go to the ER, because even in my temporarily psychotic state I knew that I wasn’t actually dying, and my boyfriend knew, too. According to a study from 2022 on a quarter of a million regular cannabis users, only about a half of one percent reported going to the ER for a cannabis-related psychotic episode. But I’m pretty sure a lot more people have had some experience where they didn’t go to the hospital like me.
Because of the ability of cannabis to cause those kinds of experiences, it’s certainly fair to wonder if cannabis might actually trigger a serious psychosis in some people. There have been a LOT of studies on this, most of which have the same lack of causation as in the anxiety studies: maybe cannabis leads to an increase in schizophrenia risk, or maybe cannabis use is just one of the many behaviors that researchers believe are warning signs of a future diagnosis, along with alcohol use, tobacco use, and poor performance in school.
That said, last year researchers published a massive study on Danish cannabis users that isn’t a slam dunk for causation but makes a very good case: amongst 7 million people, those with “cannabis use disorder” (a kind of addiction in which people continue to use despite the drug negatively impacting their life) had an increased risk of schizophrenia, especially among men.
They also found that as cannabis increased in both availability and potency from 1972 to 2021, the number of schizophrenia diagnoses rose in exactly the way we’d expect to see if there was a causal link, with a particularly strong connection for young men. Again: not proof of causality, just evidence for it. And compelling enough evidence to caution younger people from frequent or heavy use of cannabis while they’re still in that age range when these disorders are usually identified, meaning under the age of 25. That’s right, you thought rental car companies chose “25” at random but it’s actually an important protection to make sure you don’t have a psychotic episode while driving home from the airport. Now you know.
Anyway, any connection between cannabis and schizophrenia, even if causal, would still represent a very rare risk. Which brings me to the other related subject I have to bring up: even with an increase following various states decriminalizing and legalizing cannabis, the number of people showing up at an emergency room for cannabis pales in comparison to other drugs. Cannabis doesn’t even get a shoutout in this pamphlet showing ER visits by drug type during COVID: the worst offender was opioids, driven in large part by fentanyl. And even then, THOSE numbers can’t compare to ER visits that happen due to alcohol, which are an order of magnitude bigger: 400,000 visits in just 2017, compared to literally every other drug, which was about 5,000 per month or 60,000 for the year.
If you’re going to worry about a drug screwing up your own health or the health of kids, booze is the one to go after. And that includes anxiety, the correlation that kicked off this video: research shows that people with anxiety are at an increased risk of alcohol use disorder, likely because alcohol can calm anxiety in the moment. But unfortunately, the next day the anxious person’s brain can experience a corresponding spike in even MORE anxiety thanks to alcohol screwing with neurotransmitters and interfering with sleep patterns. How do you make the anxiety go away again? That’s right, more alcohol! Wash, rinse, repeat. It’s much, much more dangerous than any suspected connection between anxiety and cannabis.
That said, if you’re under 25, male, with a family history of schizophrenia, maybe don’t get into cannabis as a hobby. And if you have severe anxiety and want to experiment with cannabis for treating it, start small. Cannabis affects people in different ways – for me it often just deletes the anxiety but I know some people who feel like any amount of THC makes them paranoid and more anxious in general. Just please take it in a safe space, and if you don’t have a friend to babysit you, go ahead and queue up this excellent video from Lifehacker. Yep. Been there.