in: Health, Health & Fitness, Podcast

• Last updated: March 13, 2024

Podcast #920: Is Cannabis a Safe Drug?

Over the last decade, cannabis use has been legalized in more states. At the same time, the idea that marijuana is a safe drug has steadily increased.

But is this an accurate perception?

Recent research by my guest, Dr. Ryan Sultan, a professor of clinical psychiatry at Columbia University, casts some doubt on a universally affirmative answer to that question, and he says we need to be having a more objective, balanced, and nuanced conversation around cannabis than we currently are. We have exactly that kind of conversation today on the show. We dig into the fact that young adulta are the group most vulnerable to the potentially negative effects of cannabis and how marijuana use in adolescence is linked to both mental illness and cognitive deficits. Dr. Sultan unpacks how cannabis impacts the developing brain and may lead to schizophrenia, especially in males. We also talk about whether if you used marijuana as a young adult and then stopped, your brain can still recover, and a cannabis-related health concern for all ages that doesn’t concern the brain. We end our show with Dr. Sultan’s take on what the safe use of cannabis looks like for adults.

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Read the Transcript

Brett McKay: Brett McKay here and welcome to another edition of The Art of Manliness podcast. Over the last decade, cannabis use has been legalized in more states at the same time The idea that marijuana is a safe drug has steadily increased, but is this an accurate perception? Recent research by my guest, Dr. Ryan Sultan, professor of clinical psychiatry at Columbia University, cast some doubt on a universally affirmative answer to that question. And he says, we need to be having a more objective, balanced, and nuanced conversation around cannabis than we currently are. We have exactly that kind of conversation today on the show. We dig into the fact that young adults are the group most vulnerable to the potentially negative effects of cannabis, and how marijuana use in adolescence is linked to both mental illness and cognitive deficits. Dr. Sultan impacts how cannabis impacts the developing brain. It may lead to schizophrenia, especially in males. We also talk about whether if you used marijuana as young adult and then stopped, your brain can still recover. And a cannabis related health concern for all ages. That doesn’t concern the brain. We end Show with Dr. Sultan’s. Take on what the safe use of cannabis looks like for adults. After the show’s over, check out our show notes at All right, Dr. Ryan sultan, welcome to the show.

Dr. Ryan Sultan: Thank you. I’m excited to be here.

Brett McKay: So you are a professor of clinical psychiatry at Columbia University, and you’ve done a lot of research on ADHD and teenagers and young people. Recently you’ve been doing some research on cannabis and how it affects the psyche. What led you down that research path?

Dr. Ryan Sultan: So for me, I’ve always been interested in mental health. At a young age, I identified it as something that I felt we weren’t thinking enough about. I’m in an age group where I think I feel much more acutely the historical stigma of mental health, obviously it’s improved. And so, so that led me on that path. And ADHD was something I became very interested in for a variety of reasons. One of the main reasons is I come from a family of people with ADHD. I have ADHD, and I wanted to learn and understand more about it and how to treat it and, you know, what’s effective and why we have it, and how does it fit into a historical context. And I followed that for a while and, and and really expanded my knowledge and expertise on that.

And as I was sort of coming to what it felt like a, you know, like an, like an end of that story for me, from a, at least from a research point of view, I was really struck by how ADHD and substance use are just so, so linked. I mean, they’re like, they’re like cousins. They’re very commonly connected to one another. ADHD is a major risk factor for substance use. And a lot of the, the ways we think about like the brain and neurobiology, there’s a lot of overlap between ADHD and substance use. And then the pandemic happened. And like a lot of us, I was sort of thinking during the pandemic and marijuana was being discussed a lot. And I noticed a very significant shift in attitudes around marijuana. I went to high school in the nineties, late nineties.

And so I was on the tail end of like dare and like the drug wars. And so, you know, it was very meaningful for me to see it being presented in this other way. And as the pandemic was ending, you know, and I’m going out, I’m taking my dog for a walk in the morning. I live in New York City I Live in Manhattan. I started noticing the number of people smoking weed on the streets. I was like, okay, well, it’s decriminalize, now They can do that. Though It seemed like a lot. And I was a little struck by that. But the thing that really struck me and disturbed me some is that I would regularly see teenagers in middle school, kids in Manhattan, in New York in the morning before school getting high, like smoking joints getting high.

And I would go up and I would talk to them about this and ask them questions. And you know, it’s clear that they, they considered it to be a very benign thing. And that’s actually supported by survey data, which shows that most people now see marijuana as totally benign. And what I found to be really striking about it was that there’s no way that this is benign for them. Like anyone who’s ever gotten high would agree that you don’t get high before you’re going to do something involved in learning. Just like you wouldn’t get drunk before doing that. It’s gonna adversely affect your ability to learn. And so that sort of put me on a course of like, what do we really know about cannabis? Particularly what do we know about cannabis in teens? And the more and more I learned about it, the more and more I realized, we actually didn’t know very much at all that the information that we had was really rather dated because it was done before that We weren’t allowed to do federally funded research around on cannabis.

And that it was not just dated temporarily, meaning it was published a long time ago, but it’s obsolete because the cannabis of today is significantly more potent than the cannabis of the past. Depending on what you look at. I mean, some of these places say that they have 90% potency cannabis. The cannabis of like my parent’s generation of like a hippie generation was like 3%, 5%. So this increase in potency means we’re not really dealing with the same substance anymore. So like, do we know enough about this new substance? How do we look at that? How do we think about that? So I really wanted to start to think about that and, and learn about that and understand and expand our knowledge as a society around cannabis as we enter into this new phase where use is gonna increase really substantially.

Brett McKay: Something you mentioned you’ve noticed in Manhattan changing attitudes around marijuana and you’re seeing more people use it in, you know, openly. I’m in Oklahoma, we have medical marijuana, which is basically recreational marijuana. ’cause it’s so easy to get a marijuana medical license card because there’s billboard saying, Hey, here’s this doctor. Get a card. And it’s been interesting to see in Oklahoma, just out in public, you’ll be at a kid’s like my kid’s basketball game. And in some rural, like small town in Oklahoma, and maybe 20 years ago you would’ve smelled like cigarette smoke on the parents in the stands. Now you just like, people smell dank. I’m like that’s [laughter] That’s interesting. And yeah, just to see that shift that’s happened, like really in like the past 10 years, it’s, it’s interesting to observe that.

Dr. Ryan Sultan: I think, To sort of touch on the medical thing, you know, My frustration around legalization of cannabis has not been the legalization of cannabis. It’s been when we pretend it’s a medical thing, but it’s not really a medical thing. Like, let’s be straight guys. Like if we want it to be a legalized recreational drug, and that’s a decision we want to make as a society, like let’s make that, let’s not pretend it’s medicinal because the science on like medicinal marijuana is not very strong. It’s really solid around like reducing nausea, weight gain. Like it’s definitely good at that. Acutely, it’s meaning like right after you use it usually reduces anxiety though in the long term when you use it continuously, it’s pretty clear that it actually increases anxiety. With depression, again it’s probably gonna make you feel better if you’re not feeling very good at the time and you’re feeling down and depressed. But similar to alcohol, like it’s not a permanent improvement. Often you end up needing… If it’s a major coping mechanism for you, if you’re using it medicinally for like a mental health point of view, you need to use it more frequently and in higher dosages to get the same effect. And I think it’s important that people understand that, that that’s a trade off that they’re making around that.

Brett McKay: Well let’s dig into a recent study you did that looked specifically at cannabis use amongst teenagers, young people. And you looked at what’s called non-disordered cannabis use and disordered cannabis use. What’s the definition of those and how are they differentiated? And how did you do that in your study?

Dr. Ryan Sultan: Great. So let’s think about how to talk about this in a way I think that’s helpful to your audience because there’s two sides of it. I think some of it is a little more nerdy, sciencey and other parts of it I think are a little more useful and practical. So one of the questions that I had for myself is, as we’re entering into this world where cannabis is becoming a commonly used, openly an accepted recreational substance like alcohol is, we don’t have as clear an idea on like what level of cannabis use qualifies as problematic from like an addiction point of view versus what qualifies as just sort of like okay and recreational. And so what I wanted to do is try to understand that a little bit better. So I wanted to start with teenagers ’cause we know that teenage brains are still undergoing development.

It’s funny you know, 18, you’re an adult, but that number is very arbitrary. Your mind is not done developing. All of our minds are not done developing until we’re 25. If you have ADHD, it’s probably like 27, 28. And it continues to go through all these structural changes where, things are being myelinated, which basically means like, it’s like upgrading your brain from like dial up to like Files or something like that. So that’s important ’cause it allows your brain to develop more sophisticated thinking skills like judgment and impulsivity gets reduced. All the sort of higher level cognitive skills that come a little later in life and that are really important. And so the idea of exposure to cannabis during that time period is there’s a lot of evidence around that it changes some of that structural brain remodeling that occurs.

So I wanted to start with teenagers and get an understanding of that. So what we did is we had about 70,000 12 to 17-year-olds that we looked at. And this is a nationally representative sample, which is really cool because it means like whatever statements come out of this are statements that you can make kind of universally around the entire US population as opposed to if I just talk to 70,000 random teenagers, it’s actually been done in a way that it encompasses large numbers of people and the different demographics. And what we did is we basically said, “Well, have you recently used cannabis?” And if you hadn’t recently been using cannabis, you got put in the non-use category. If you had recently used cannabis, we then had a second set of questions that were asked of you. And those questions are the questions used to diagnose if you have an official addiction and then if you qualified for having an official addiction, which you only had to answer positively to two out of the 10 questions. Then you have the substance use disorder. If you didn’t, you went in this non disorder group, which is this group of people that are saying they’re using marijuana, but we can find no evidence that this is a substance use problem. So non-disordered, no substance use problem, disordered, substance use problem.

Brett McKay: Gotcha. So it’s like the difference between like maybe an alcoholic and then someone who has a drink every now and then?

Dr. Ryan Sultan: Mm-hmm.

Brett McKay: Okay. So this study looked at a couple of things and one was the prevalence of this non-disordered cannabis use. So young people who responded to the survey said, I use it but I’m not addicted. What did the study uncover on that front?

Dr. Ryan Sultan: So what we found is, and again among recent marijuana users, this is not I’ve ever used marijuana more. These are people that are probably using marijuana regularly at this time. That the people with non-disordered ones, the one that are recreational, they’re four times as common as those that meet the criteria for having a problem that we would say with their cannabis use. So overall about like 13% of US teens between 12 and 17 had recent cannabis use and maybe like 2.5% to 3% of them had that like kind of addictive stuff going on. And that other rest of them, the 10% are using, but they don’t qualify as having a substance use problem.

Brett McKay: When you did the survey and you got the results back, was the rate of cannabis use, whether non-disordered or disordered, was it higher or lower than you expected?

Dr. Ryan Sultan: It’s lower than I expect. And part of that may be, I live in New York City and it’s a very progressive city. And in a post-pandemic world, it is disturbingly easy to get cannabis. There are all these little like pop-up, not legal, unlicensed cannabis shops that have proliferated. So to me that number feels lower because remember we’re averaging right? So like my good buddy lives in Montana and I spent a lot of time out there with him and his family and I’m pretty sure that that rate is a lot lower in Montana. So we’re getting an average. So that explains part of it. And then the other part of it is when you ask someone, and this isn’t just teenagers, this is you and me too. You ask them like, how much do you smoke? How often do you smoke? Or you ask them, how much do you drink? How often do you drink? We’re all lying and we’re lying to ourselves, not lying intentionally. We’re lying ’cause like, I don’t know, like we all wanna believe in our head that these things are happening less often than they actually are. And I can tell you from my own personal experience doing this activity.

Friends, family and certain, a lot of patients where I say like, actually let’s log what you’re doing. Let’s actually write it down every day. That people are always underestimating it, right? So, another factor may be that people are underestimating it, and that’s something that we’ve seen and it’s a huge problem actually from a research point of view, is that, because people underestimate it makes it harder to study it.

Brett McKay: Are there historical surveys about cannabis use amongst adolescents? So do we know if it’s increased or stayed the same over time?

Dr. Ryan Sultan: Yeah, the general trend is that it’s increased, depends on what time period you look at. But in the last 12 years, there’s been almost a doubling in the frequency that a teenager would report that they’ve used cannabis.

Brett McKay: You mentioned earlier one of the things you were wanting to explore in terms of marijuana that got you thinking about it, was this change in perception of cannabis safety. And I guess over time it’s been seen as more safe. Is that what your research is finding?

Dr. Ryan Sultan: Yeah, that’s absolutely been shown. So in that same time period of like the last 12 years where I said that we’ve almost doubled the number of youth that say they’ve used cannabis, if you ask the same question and this, the data from the study comes from a national Institute on drug abuse, actually funded my research as well. And they do this very comprehensive survey every year. And so they ask the same questions so we can look at it. So if you look in the past, so like 10 years ago, 50% of people would’ve said yes to the following question. I think that weekly cannabis use is safe and like not harmful. Now it’s 75, 80% of the population, say that.

Brett McKay: Wow, okay. That’s a big increase.

Dr. Ryan Sultan: Which is like, I mean, that’s like almost everyone, right? I mean that’s a lot of people and especially among kids. Among adults I think the jury is out, around what is the actual risk associated with that. But among youth, that’s pretty much not true. That there is no negative effects of it. Even before the study that, I did the one that we’re talking about, there are stacks of research papers, from many different avenues discussing how cannabis use in young brains seems to change actually how the brain develops the morphology of the brain, the connections that are being made. It clearly causes cognitive impairments. I mean, anyone who’s ever gotten high and tried to do math will tell you that it causes cognitive impairments and that those cognitive impairments persist in many cases six weeks out, like six months out. And that long-term cannabis use starting in younger years can be associated with an eight point drop in your IQ. So my point, I guess is that that’s at least among youth, that that’s actually not really an accurate perception.

Brett McKay: Well, let’s dig into this guys. The second thing this study looked at was what adverse effects are associated with non disordered cannabis use? These are teenagers who are smoking marijuana maybe a couple times a week, but they’re not addicted or whatever. So you mentioned some of the adverse effects of cognitive decline. What are some other ones that you found in your study?

Dr. Ryan Sultan: I love that you said associated, that makes me so happy that you are making that distinction. I’ve had multiple podcasts on this and I’ve had to jump in. I’m like, stop saying effect.

Brett McKay: Right?

Dr. Ryan Sultan: We’re not, we can’t prove that. So associated is right. So it’s really hard to prove causality in science, in the things I’m about to talk about. There is a fair line towards causality because we have multiple different lines of evidence, multiple different ways showing something similar that these things are problematic. But what I was trying to do is figure out what I was actually really curious about is like, all right, so by definition in psychiatry we make the cutoffs for what we consider to be an addiction, what we consider to be a substance use problem. We make those cutoffs based on is the thing having a negative impact on them. And so I was like, okay, so we would expect that the ones that have a substance use problem, that they’re going to have higher rates of depression, higher rates of suicidal thoughts, cognitive problems associated with the cannabis. Truancy. They’re not going to school. Their GPA is gonna be poor, that they’re gonna get into delinquency problems. You’d expect that that’s very consistent with the definition. What I was surprised by was that when we looked at these non disorder guys, right, so these are the ones that do not meet the criteria for a substance use problem that they also had increases in their likelihood of having a recent major depressive episode. Having suicidal thoughts, skipping school, having a low GPA, and those were meaningfully higher than you would if you reported yourself as a not recent user.

Brett McKay: Okay, right now we can just see correlation maybe some causation. There are some, you’ve said there are some studies that show maybe there is some causation going on.

Dr. Ryan Sultan: Yeah, absolutely. And when we think about it, so let me sort of tell you how I think about this. So when this first came out, I’m on Reddit a lot. I like Reddit. I think it’s fun. So there’s this section on Reddit called science and it’s definitely one of the like meteor Reddit groups sort that I’m a part of. And so it pops up and I see this article that of course catches my attention because it’s about cannabis use in teens. And I realize it’s actually my article. And I’m like okay. So I’m like clicking on this and it has like over 3000 comments, which is like that’s like a lot of comments. But it actually never rises to a level where it gets a high rating. I don’t know if you don’t read it like you can down and upvote things.

So you could undo people’s likes. And it was close to neutral. And I was like, what’s going on here? And there were so many people up and down voting it. And so I was like okay let’s take a look at this. So I went of the comments and it was so clear how to get into this idea of causation, how people’s views were very different on it. So we had like two main groups. So one group was the, this proves what I already know that cannabis is B-A-D, bad. My uncle, my sister, my brother, my niece, they were using cannabis and it made their depression worse. Like of course. And then you had this other group of people that said no no no no no, you have it all wrong. You have it all wrong. The cannabis has nothing to do with this.

They just happen to be using cannabis because they’re already depressed and they’re using it to moderate and improve their symptoms and quality of life and reduce their anxiety. And so there was a lot of these disagreements going back and forth. And for me what I think is really important about that, and the way I think the frame, the findings that this study has, which is this association with depression and suicidal thoughts and poor academic performance among people kids who use cannabis but don’t have like an addiction, is that there’s a negative feedback loop that happens. So let’s imagine that we have a young person that is predisposed to depression. Maybe they’re not depressed at the moment, so they have a genetic predisposition some things going on in their life that might set it off. There’s trouble at home.

Maybe they change schools. They’re not having good social situation. They use cannabis maybe even use it with their friends. They vape. And if they’re not feeling great, cannabis may temporarily, will probably temporarily make them feel better. And so there’s a relief that comes from that. Now the problem is that let’s say we keep doing that. Let’s say that this becomes a regular coping strategy for someone. The repeated use is definitely not going to improve your depression. That is not a treatment for depression. We have not found it to be a true depression. We have many treatments for depression that are very useful. This is not one of them, but that it’s more likely actually to worsen their depression over time, to worsen their anxiety over time. You can imagine someone that is getting high regularly, they’re gonna be lower energy they’re gonna stay at home more. So fewer social encounters which that’s a predictor for depression. Their academic performance is not going to improve, anything that’s gonna get worse under this. So it becomes like a feedback loop where, you may have entered into this feedback loop with the relief that comes from this. You might even have been predisposed to getting these things. But that if you develop sort of regular use that you’re actually setting in motion potentially like a snowball effect that just keeps making this worse for you.

Brett McKay: Okay. So kids might be starting marijuana to self-medicate ’cause they have anxiety, depression et cetera. But then the marijuana use will just exacerbate those problems in the long run.

Dr. Ryan Sultan: For many, I mean and not everyone. Like I was in a meeting yesterday with a number of people that are interested in cannabis and wanna do some testing on it. And they were all talking about when they first started using cannabis and many of them started using when they were younger and they’ve gone on and done okay. Like not everyone is going to have those issues but that the likelihood of them going up, is significantly increased. And so like in my study, you’re gonna find that there’s a 200% to 400% increase in the likelihood of having a major depression, of having suicidal thoughts, of having these cognitive impairments, of skipping school, of having a low GPA. They’re gonna be a lot higher, a lot higher, not as high as if you had a substance use problem like that official addiction. But meaningfully higher than if you are not using cannabis.

Brett McKay: Okay. So even the non-disordered cannabis users experience significantly higher mental and behavioral problems than non-users.

Dr. Ryan Sultan: And like if someone wants to look up the article, they can they can Google it. It’s an open-source article and JAMA Network Open. And you can actually look at the figure one is a great table that explains it. It’s just Google salted, non-sorted cannabis use should come up. It’s actually looks like steps. So it’s step one is non-users, then it’s like a his so then the next bar is almost double and that’s the non-disordered users. And then the next bar is increased even more. And those are the people with addiction. So it’s a stepwise trend. I’m doing another analysis now, that looks at it based on frequency of use. And it’s pretty clear that, frequency of use follows this same pattern. So the more that you’re using the worse these outcomes are.

Brett McKay: We’re gonna take a quick break for you word from our sponsors. And now back to the show. Another adverse outcome I’ve seen lately in the news is schizophrenia. The connection between marijuana use in young people in schizophrenia later on in life. What is that research showing?

Dr. Ryan Sultan: It’s as compelling as what we’re talking about now, a bit to me more disturbing in some ways. So schizophrenia is like a super serious condition. It’s a neurodegenerative disease and it really alters a person’s life course and it significantly affects their family members. So it’s really something that we want to be doing everything we can to prevent, because once someone has it our treatments for schizophrenia are, they’re fine and they help but they’re really not great. Out of all of our mental health conditions, it’s probably one of the ones that we have the poorest ability to treat. So in thinking about how to prevent that, there’s just been this thing that we’ve noticed for a long time, which is that people when they first develop schizophrenia, which tend to develop like late teenage years, to around 30 that the likelihood that that person has a positive urine drug screen or reports recent cannabis use is like really really high.

And in fact, when I have a new episode of schizophrenia or psychosis we could generally describe it as, I mean it’s the exception not the rule when you test their urine and it’s not positive for cannabis. So we noticed this link and there’s been multiple studies there’s just another recent study on this, where it looks like in certainly in guise this is more true for men between the age of like I think 18 to like 26, cannabis use increases the likelihood of development attenuated by four times.

Brett McKay: Wow.

Dr. Ryan Sultan: Which is a lot. I mean for me one of the things I talk about, because I work with a lot of young people and when they’re using cannabis or if they’re thinking about it my thought is always like, look if you wanna use cannabis that’s your decision.

Like okay but like if you want to go off the scientific research it actually would say that you should wait until you’re around 25. This risk of schizophrenia drops really substantial issues. The association between cannabis and schizophrenia is not nearly as strong later on. And the idea is like your brain is still developing. Getting back to this my brain is not developed, my brain is not developed. Schizophrenia is very much a disease of your brain. A condition of your brain. And so when you have cannabinoid receptors which are these receptors that we all have, that cannabis binds to and by the way we all have our own internal cannabinoids that your system just makes on their own. Just like you have testosterone and you could take exogenous testosterone, you’re taking exogenous cannabinoids that are actually much stronger than your cannabinoids.

And there are these receptors all over your brain. And so when your brain is developing, it’s easy to see how exposure to these things is going to disrupt the development of your brain and potentially increase the risk of depression, anxiety, definitely schizophrenia. And certainly also the risk of not being able to manage substance use later in life. ‘Cause one of the things that, I think we all struggle with is, okay you can drink alcohol but can you drink alcohol in a way that it is overall giving you a net gain in your life? And so what’s that question with cannabis? Like where do we sort of draw that line in terms of what is an appropriate amount that people are using and what is an age to start? And so when I talk about this with youth, I really encourage them to wait till like 25, because the science really says that your brain is now done developing at that time period. And the likelihood that when you’re an adult that if you use alcohol, if you use cannabis or use another substance that’s potentially addictive, that you use it in a healthy way, meaning it doesn’t end up causing problems in your life, is much much much higher. The later you start, the earlier you start, the likelihood that it’s a problem is significantly higher.

Brett McKay: Okay. We’ve been talking about there’s a correlation causation, there’s research that there is a causative factor going on. So you mentioned what might be going on. So these cannabinoids are somehow disrupting the developing brain. Like do we know exactly what’s happening to the brain, particularly a young person’s brain that the THC or whatever it is, disrupts the development? Like do we have an idea of what’s actually going on?

Dr. Ryan Sultan: Well, we have a pretty good idea around it. I mean your brain’s development is, I mean the levels of complexity around it are mind-boggling. I’ve been in training for mental health and neuroscience and the brain for many many many years. I guess it probably started for me in like 2007. I am been in a research track on this now for five years and I’m still learning around the complexity of that. But like very broadly, the cannabinoid receptors play a role for teens in what happens to your brain and how it develops, how does it prune properly? How much gray versus white matter that you have the morphology and size of different parts of your brain? And there are a lot of studies, I was actually just flipping through it before we got on that consistently show changes in the morphology of the brain as well as tests that test how well your brain is working. Like how quickly can you think of something? How well can you remember something, very consistently shown in everything from rodent models through actual people? And so when in science you keep finding the same or similar things in different places, that’s usually a really good signal that there’s something going on there.

Brett McKay: So when you say morphology like that that’s like the size of the brain.

Dr. Ryan Sultan: The size, yep. Mostly referring to like atrophy.

Brett McKay: So you guys see your brain gets smaller if you use marijuana early in adolescence?

Dr. Ryan Sultan: Yeah. Parts of your brain.

Brett McKay: Parts of your brain. Like the prefrontal cortex might be… That’s probably where you get a lot of that gets hit hard, because that’s what’s developing when you’re an adolescent is that prefrontal cortex.

Dr. Ryan Sultan: And you want to develop. Like so this is really important. One of the jokes I make is like your, car insurance goes down at 25. Do you know why your car insurance goes down at 25? Because you have fewer accidents. Do you know why you have fewer accidents? ’cause your prefrontal cortex has been developed. [laughter] And you can make much better decisions. You can gauge size, you can predict things much better. Your judgment has been Im improved. Your impulsivity has dropped substantially.

Brett McKay: So you mentioned also, I just wanna recap this, the earlier you use marijuana as a teenager, you’re probably gonna have those adverse effects compared to later correct?

Dr. Ryan Sultan: Yeah. So the there’s several things. So like the likelihood of having depression, the likelihood of having suicidal thoughts, the likelihood of having poor academic performance, the likelihood that you go on to actually have a substance use problem, is all very highly linked to when you start using.

Brett McKay: Let’s say there’s a person who started using cannabis 15, 16 they got really into it and then they stopped. Is the risk of increasing mental deficits or mental illness later on in life? Is it still gonna be higher than if they’d never used the stuff?

Dr. Ryan Sultan: Yeah, I can think we can say pretty confidently that they put themselves on a different trajectory but that the decision to sort of limit that use later is also putting them on a different trajectory than if they had stayed on that. And that there is evidence there’s one study that shows that long abstinence like eight years that the brain seems to heal itself. And that in that eight-year time period which is like a long time, that their brains looked fairly similar to controls. There were some differences but that there is some healing that goes on which is cool. Like we used to think that the brain, I was taught in high school like your brain can’t regenerate it can’t regrow but that’s actually not true. It can.

Brett McKay: Okay, so marijuana use as a teenager can increase severe depression, anxiety. I think also suicidality was another thing. You looked at schizophrenia, but then also I think you mentioned it also affects you cognitively, you’ll have cognitive deficits that are associated with cannabis use as a teenager. Like your IQ will be lower correct?

Dr. Ryan Sultan: Yeah. I mean this is one of the things I wish actually people wanna talk about like the mental health from a depression, suicidal, schizophrenia point of view. And those are super important. As a person who is sub-specialized in like child and adolescent psych, I think a lot about learning and development from a learning point of view. And your job until you are 18, your primary job is to go to school. Your primary job is to learn. We have a whole school system set up to hopefully help you develop critical thinking skills, help you learn knowledge that’s going to help you and assist you in your life, whether it’s at a trade school, whether it’s an intellectual academic activity and that’s your main job. And regular marijuana use is unequivocally disrupting your ability to do that. And if the marijuana use is moderating a problem you have like anxiety or depression, I get that. It’s really not a great way to treat that. There are much better ways that we have to treat that, that are not gonna impair your cognition and your learning. Which is, I guess I just find that very upsetting ’cause I want young people to be learning. [laughter] Your brains are primed to learn at that point. They’re actually really good at learning.

Brett McKay: So you mentioned you saw this with the your Reddit post that got a lot of comments but it seems like whenever people bring up possible adverse effects associated with cannabis use, there’s pushback. People are like, “Well, no actually it could be this that reason why people use marijuana. It’s not the marijuana.” Some people seem really invested in seeing cannabis as a safe drug. What do you think is going on there? Why the pushback?

Dr. Ryan Sultan: I mean there’s a lot going on there. I think at a basic level. There’s a whole group of people that feel incredibly validated now that something that was demonized for so long, is being given credit as at least not being the incredibly detrimental drug that it was portrayed as. And that was wrong. Marijuana is not as evil as we were told historically, that they’re right about that. I think that that’s one aspect of it. I think another aspect of it is that there’s a lot of people that are trying to capitalize on this, from a development of products point of view in the US, So there’s a lot of PR being done around marijuana. And so people are becoming more comfortable with it. And that’s a snowball effect. The more people are comfortable, the more other people become comfortable, the more we talk about it.

And so I think that we’re still on the upswing of marijuana’s great. Marijuana’s great, marijuana’s great. It’s totally fine. But for me as someone who’s thinking about this, I think a little more bird’s eye view than the general public. I think that we are, the pendulum has now swung too far to the other side. And that we need to sort of step back and start saying wait a second. Marijuana’s actually not a panacea treatment for everything that’s just crazy and wrong. That it’s not totally benign. That we need to be thinking about what are appropriate limits and sets and also what are quality control things. So the meaning I had yesterday that I was mentioning to the people who had said they had used at different ages, one of the things we’re doing is actually trying to use advanced organic chemistry methods, to take samples of marijuana and evaluate essentially the purity of them, the quality of them.

Do they have pesticides in them? How much of them is actually the THC cannabis or CBD product that it’s supposed to be and how much of it is other stuff. And our preliminary results suggest that it’s much more heterogeneous than you would like it to be, as opposed to alcohol which is not it’s alcohol’s highly regulated and you know what you’re getting and you’re not gonna go buy alcohol at a liquor store and be worried that it’s poisoned with something.

Brett McKay: Yes, at least with fentanyl or something like that.

Dr. Ryan Sultan: And we don’t have that at the moment. I mean God, we have not found that I mean we we’re joking yesterday about like are we gonna find that? Like we have not found that yet. I mean that would be really upsetting. Like even if we took say 500 samples and one of them was laced with fentanyl I think that would still be really really upsetting.

I think that’s one thing we’d have to worry about. But there’s also other things we have to worry about. This is a plant that people are growing. So like are they using pesticides? What compounds are they using to get the thing to grow? What things are they using to dry it? What things are being added on? And that’s happened already and hit the news. Like if you remember the whole vaping thing that happened where all these people were getting these long illnesses from vapes, and they were putting some sort of I can’t remember what it was but some sort of compound that they were using to sort of like clean or extract it was incredibly toxic, incredibly, incredibly toxic. And I worry about that with cannabis. So there’s another study that came out that again is really I think very impactful to me.

So like you know what a chest x-ray is? We scan your chest we see what it looks like. We do chest X-rays to look for lung cancer. We do chest X-rays to look for pneumonia. We do chest X-rays to look for emphysema COPD. Emphysema COPD lung cancer have been dropping for a long time because cigarettes are just nails in your coffin. Like we worked really hard to get people to stop smoking. So what they did is, they did a study where they looked at people that didn’t smoke anything at all. That’s a group of people, who smoke cigarettes regularly, that’s a group of people. And then people that smoke marijuana regularly. And when I saw this like a like it’s a headline I was like why is this so a big deal?

Of course, it’s gonna show that the cigarette smokers have the worst ones. We all know cigarette smoke is bad and there’s all these nasty things in it. Nope. Overwhelmingly the cannabis users’ lungs looked the worst. And they were at the greatest evidence and risk for COPD and emphysema. And I was shocked by that. Like I have been talking to everyone who uses marijuana since then and I was like can you please use it in like another way? Like, take an edible like let’s can we at least use like I don’t know maybe like a bong the water cleans it. Like when the vape, if I don’t know if you’ve ever seen a bong it gets really dirty at the bottom. And I always think well that’s good. That’s not going in your lungs. So there’s a lot around this and I think that getting back to your idea of like why are we so unwilling to hear the other side of this?

I think the pendulum has been really kind of swinging too far to the other side. And we need to pull it back a little bit and really think about this objectively. There’s a there’s a theory we talk about in psychotherapy that Melanie Klein developed the idea of being able to see a whole object, being able to see the good and the bad of it’s referring to people. So like instead of just seeing a person as all good, you love them or all bad and they’re terrible, you’re like well actually people are a mixture of like good and bad things and everyone is, marijuana’s the same way. It’s a mixture of good and bad stuff and we have to be objective in really thinking about where it lies on this good or bad mixture and educating the general public so that they can make an informed decision. And now I’m talking about adults, they can make an informed decision about whether they wanna use this stuff like and like what the advantage might be for them and what are the potential disadvantages for them.

Brett McKay: Well, you’ve said that you’re looking at this from a bird’s eye view. What do you think are the possible societal implications of the rising rates of cannabis use amongst particularly young people? Because that’s what you’re focused on like long term, are there problems we might be seeing because of the rising use that we’re not seeing now but we will later on?

Dr. Ryan Sultan: I mean my hope actually is that we do enough research that is then available to policymakers. ‘Cause right now like states have made their own decisions they’re it’s a little bit of a free for all that creates a safe environment and promotes safe use of cannabis. And that we actually don’t have these problems. That’s actually really like where we’re hoping to go. And I think it’s not too late for that. But what would be my concern, my concern is for smoking cannabis. My concern is lung diseases across the board, particularly in youth theory you start, my concern is that it is halting the development of whole groups of kids that are not going to progress in their life in the same way that they would’ve, because they’re more likely to have these mental health conditions because they’re less likely to be engaged appropriately in their scholastic environments because they’re having cognitive problems.

And that’s really unfair to them. And I feel like I’m gonna get on a soapbox for a second here. Like I feel like we’re failing them as a society by permitting that to occur. And there’s a lot of parents that are not concerned about it because they’ve been told and given the impression not to be concerned about it. One of the take-home messages that I try to give to people about this is like, look whether you believe that cannabis is causing these problems or not like let’s even forget about that. The bottom line is, when you look at large groups of kids as larger group of kids as you can look at in the US, these things are linked. So at the very least, they’re risk markers. They’re an indicator. So if you know a teenager and you’re an educator, you’re a parent, you’re a relative, you are a healthcare provider and they’re using regular cannabis your antenna needs to go up, needs to go up, and say wow actually this kid is two to four times more likely to have a depressive episode to have suicidal thoughts.

They’re way more likely to be performing poorly in school, skipping school having cognitive problems. Like what do I need to do to make sure that they don’t have that? Like I need to screen them, I need to keep an eye on this. Make sure that’s not what’s going on with them. And if they’re having those problems which statistically they probably are, how do I help them? How do I intervene in a way? So take depression. There’s many ways to treat depression. Physical activity is a well-documented way to improve depression. Exposure to nature is a well-documented way. Protective for depression, improving social relationships connections between family members and peers. Very great way to improve depression. There are many types of psychotherapy that we use for improving depression. There are medications we have for improving depression. These are all things that are well supported in the evidence scientifically and that we know what the downsides of them are very clearly. And you can make an informed decision around that. Cannabis is not a treatment for depression. It’s not likely to improve your depression anything more than for a short period of time which from my point of view as a psychiatrist as a mental health doctor is not treating your depression, making your symptoms go away briefly is a relief, that’s not really a treatment that’s helpful for you in the long run.

Brett McKay: If someone were to ask you straight up is cannabis safe? How would you answer? I think we’ve kind of like seen that throughout this conversation. You’d say it’s nuanced it depends right?

Dr. Ryan Sultan: Yeah. Is cannabis safe among over 25-year-olds if the cannabis that you’re getting is of good quality which I think is something that there’s still the jury is out on, and you are ingesting it probably as like an I would say certainly edible would be kind of the safest. And you’re using it infrequently. It’s probably safe. The nuance parts of it get into frequency of use to get into the idea of how much you’re really using it. Because like anything that much like alcohol the increased use just keeps increasing the negative associations, and there’s a tipping point. So like a little bit of cannabis, I have this friend who’s a pothead who always talks about the idea of like you gotta find the magic space where you’re using just enough where it’s improving the quality of your life but not so much where it’s causing problems.

And I think that that line is not always clear to people. If I were to make a general rule right? If we’re gonna make a generalization, I think daily cannabis use is like red flaggy. That’s pretty concerning, particularly all-day cannabis use. So any of your audience that is waking up and getting high, which is a fairly common thing that’s concerning for a lot of reasons that you’re always hitting your cannabinoid receptors, you’re not really giving them much of a break. So daily use is concerning. Weekly is kind of on the cusp. Monthly the data looks like there aren’t many negative associations with that.

Brett McKay: Well, Ryan this has been a great conversation. Is there someplace people can go to learn more about what you’re doing your work?

Dr. Ryan Sultan: Yeah, a couple of places. You could go to the Columbia Psychiatry website and look up the Salton lab and you can see our past projects, this project and other projects. If you’re really nerdy you can look up the actual paper that we did on this. It’s open source paper. Anyone can read it. It’s just a PDF. So JAMA Network Open put in Ryan Sultan and cannabis use and it’ll come up.

Brett McKay: Fantastic. Well, Dr. Ryan Sultan thanks for your time. It’s been a pleasure.

Dr. Ryan Sultan: My pleasure.

Brett McKay: My guest there is Dr. Ryan Sultan. He’s a clinical psychiatrist at Columbia University and the lead author on the study non-disordered cannabis use amongst US adolescents. You can find more information about his work at his website, at the Sultan Lab at Columbia University. We got a link to in our show notes, also check out our show notes at aom is slash cannabis. We can find links to resources read all deeper into this topic.

Well, that wraps up another edition of the AOM podcast. Make sure check out our website at Find our podcast archives as well as 1,000s of articles that we’ve written over the years about pretty much anything you can think of. And if you haven’t done so already I’d appreciate if you take one minute to give your views up on our podcast or Spotify. It helps out a lot. And if you’ve done that already thank you. Please consider sharing the show with a friend or family member who think you get something out of it. As always thank you for the continued support and until next Brett McKay reminding time to listen to AOM Podcast. But put what you’ve heard into action.


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