elcome to Entanglements. In this episode, hosts Brooke Borel and Anna Rothschild ask: Is cannabis safe for people with severe mental health disorders? The emerging science that probes at this question has been particularly invoked amid legalization and decriminalization efforts.
To dig in, our hosts invited two experts with differing opinions to share their points of view, in an effort to find some common ground. The point isn’t to both-sides an issue or to try to force agreement. Instead, the show aims to explore the nuance and subtleties that are often overlooked in heated online forums or in debate-style media.
Their guests this week are Deepak Cyril D’Souza, a professor of psychiatry at Yale School of Medicine and a psychiatrist at the Veterans Affairs Connecticut Healthcare System in West Haven, Connecticut, and Matthew Hill, a neuroscientist at the University of Calgary in Canada.
Below is the full transcript of the podcast, lightly edited for clarity. New episodes drop every Monday through the end of the year. You can also subscribe to Entanglements at Apple Podcasts and Spotify.
Brooke Borel: Welcome to Entanglements, the show where we dig into some of the biggest debates in science. I’m Brooke Borel.
Anna Rothschild: And I’m Anna Rothschild. Today we’re asking: Is cannabis safe for people with serious mental illness?
Brooke Borel: Yeah, so with legalization and decriminalization happening across the country, and also rising rates of at least some mental illnesses, this seems timely. Right, Anna?
Anna Rothschild: Yeah, it’s absolutely timely. And, you know, debates over whether cannabis can affect people’s mental health have been rampant. During the election last month, Florida had an amendment on its ballot that would have legalized recreational cannabis in the state. And there were people speaking out in opposition to the measure who said there’s an association between cannabis use and all sorts of mental illnesses.
Brooke Borel: Right. And that measure didn’t pass. Right?
Anna Rothschild: It didn’t pass. But, you know, cannabis is already legal for medicinal use in Florida. And you can get a license to actually help manage certain mental health conditions.
Brooke Borel: Huh, OK.
Anna Rothschild: The law in Florida explicitly covers post-traumatic stress disorder, as it does in many other states. But depending on which clinic you go to, you could potentially get it for depression, anxiety, and more.
Brooke Borel: Yeah, this conversation is full of contradictions.
Anna Rothschild: It is. And also a lot of nuance that gets lost online.
Brooke Borel: As with most things, right?
Anna Rothschild: As with most things. And in fact, the genesis of today’s conversation started, in part, online. So I reached out to our first guest, Deepak Cyril D’Souza. He’s a psychiatrist who’s been quoted in lots of articles on cannabis’s effects on the brain. He was recently featured in a New York Times piece titled “As America’s Marijuana Use Grows, So Do the Harms.”
Brooke Borel: Yikes, I mean that’s a pretty strong statement.
Anna Rothschild: Yeah, I mean, I will say, that’s not his statement, that’s just the headline of the piece. But when I asked him “Who’s someone who holds a different view from you?” he pointed me to Matthew Hill, who’s a scientist who’d recently gone on the popular show, the Huberman Lab podcast, to refute, or like correct I guess, some of the host’s previous statements about the connection between cannabis and psychosis.
Brooke Borel: Huh, OK. So it sounds like this is a good set-up to show us this debate?
Anna Rothschild: Totally. But it ended up being a much different conversation than I assumed.
Brooke Borel: Huh, OK. I’m excited to hear.
[Music]
Anna Rothschild: Is cannabis ever safe for people with serious mental illness?
Deepak Cyril D’Souza: Generally not.
Anna Rothschild: This is Deepak Cyril D’Souza. He’s a professor of psychiatry at Yale School of Medicine and a psychiatrist at the Veterans Affairs Connecticut Healthcare System in West Haven, Connecticut. Today, he’s the director of the Yale Center for the Science of Cannabis and Cannabinoids. And in the context of this conversation, here’s what he means by serious mental illness.
Deepak Cyril D’Souza: The serious mental illnesses that most of us would agree are serious are psychotic disorders. The kind of disorders that would fall under that would include schizophrenia, schizoaffective disorder, and other psychotic disorders. So that would be one group of serious mental illnesses. I would say certain kinds of bipolar disorder would also fall in that category.
Anna Rothschild: Cyril went on to include other conditions, like depression and post-traumatic stress disorder, or PTSD. I will say, we also ended up talking about anxiety, even though he didn’t include that in the definition. But given how many people use pot to manage anxiety, I thought it would be worth sharing that part of the conversation here, too.
Brooke Borel: Yeah, that makes sense. But these are all very different conditions right? So where would you like to start?
Anna Rothschild: Yeah, let’s start off with schizophrenia. And maybe I should give a quick definition?
Brooke Borel: Yeah, let’s do that.
Anna Rothschild: OK, so schizophrenia is a condition that causes a whole range of effects. It can alter your mood and your attention span. And probably its most well-known symptom is psychosis. So, people may hear voices that other folks can’t hear. They may think they’re receiving special messages. But schizophrenia is different from patient to patient, and I don’t want to paint this with too broad a brush.
Brooke Borel: Yeah that makes sense.
Anna Rothschild: Anyway, here’s what Cyril said about cannabis use and schizophrenia.
Deepak Cyril D’Souza: I would say that most of the observational data would suggest that the use of cannabis by people with schizophrenia is associated with negative outcomes. So more hospitalizations, more ER visits, more trouble with the law, more homelessness, more non-adherence with recommended treatments, more episodes of violence, and so on and so forth.
Anna Rothschild: So here, Cyril is talking about evidence from epidemiological studies or observational studies. Basically, those are studies that look backwards to review the outcomes for patients in the real world. And despite what Cyril’s saying here, he also pointed out that many people with schizophrenia actually report that cannabis can alleviate some of their symptoms.
Brooke Borel: Ah, interesting! How does Cyril make sense of that?
Anna Rothschild: Well, Cyril also found this interesting. And he and his colleagues set up an experiment to try to figure this out.
Deepak Cyril D’Souza: I invited people, patients with schizophrenia and they got placebo, a low dose of THC and a medium dose of THC in a double-blind randomized fashion. I did not know what they were getting. The people who were rating them did not know what they’re getting.
Brooke Borel: Anna, can I break in?
Anna Rothschild: Yeah yeah, absolutely.
Brooke Borel: Just to be sure our audience knows what Cyril’s talking about here, a double-blind randomized trial, this is the gold standard for a medical trial.
Anna Rothschild: Yeah, that’s right. And in these trials, you’re able to compare different doses of drugs against a placebo, which is basically a fake treatment. It doesn’t do anything. And everything is standardized and randomized. So neither the patients nor the people monitoring the patients know who gets what. The scientists who set up the trial only find out later who got the placebo versus the real deal. In this case they used different doses of THC, the main psychoactive compound in cannabis, and compared those to a placebo.
Deepak Cyril D’Souza: What we found was that at least at the doses that we studied, it made their symptoms worse. But what may have happened is the distress related to their symptoms went down. So in some ways everybody’s right, that they were experiencing some relief of symptoms temporarily. But then what we were seeing was the increase in symptoms that persisted beyond that initial period of relief.
Anna Rothschild: You know, some people think that there is a causal link between, using cannabis and the onset of schizophrenia. What do you think about that?
Deepak Cyril D’Souza: I think there is converging and mounting evidence that heavy use of cannabis, the use of much more potent forms of cannabis, and the use of cannabis during critical stages of brain development may be associated with a higher risk of the development of schizophrenia. And when we use the word causal, I think it is really important for people to understand what that means. This debate about whether cannabis causes schizophrenia or not is uncannily similar to the discussions people were having about the relationship between smoking and lung cancer back in the 1950s.
Anna Rothschild: We’ve known for a long time that there is a relationship between smoking cigarettes and lung cancer. Smoking increases your risk of lung cancer. But some people get lung cancer without smoking. And not everyone who smokes actually gets lung cancer.
Deepak Cyril D’Souza: There is some other explanation that’s contributing to that exposure to the carcinogens that’s resulting in some people developing lung cancer and other people not. If it was just purely smoking, then everyone should develop it, right?
Brooke Borel: Interesting.Yeah, most things don’t have a perfect one-to-one causality. Right?
Anna Rothschild: Right, yeah.
Brooke Borel: There might be genetic predispositions, or certain environmental conditions at play as well. Even so, today, doctors feel comfortable saying that smoking causes lung cancer.
Anna Rothschild: Yeah, exactly. And Cyril says that cannabis meets a number of the criteria indicating that it causes schizophrenia. Not all the criteria, but some.
Brooke Borel: I see. But I mean, just how common is it to develop schizophrenia after using pot, though?
Anna Rothschild: Right. Well, there have been a number of large studies looking at this. Back in the 80s, one study found that folks who tried cannabis before the age of 18 were 2.4 times more likely to be diagnosed with schizophrenia.
Brooke Borel: Hm OK.
Anna Rothschild: And just in 2023, there was another giant study that specifically focused on people with cannabis use disorder. So, that’s people who abuse pot, they’re not casual users. And it found that up to 30 percent of cases of schizophrenia among 21- to 30-year-old men might have been prevented if they didn’t abuse cannabis.
Brooke Borel: Wow, OK, that’s more alarming than I might have imagined.
Anna Rothschild: Yeah. But remember, the vast majority of people who smoke weed do not end up with schizophrenia.
Brooke Borel: Sure, of course. We don’t want to be too sensational about this. OK, so what about safety with the other serious conditions, like bipolar disorder?
Anna Rothschild: Yeah, I asked him about that.
Deepak Cyril D’Souza: I would say it’s not safe for people with bipolar disorder. Even though it’s being used rampantly, I think, again, we see negative consequences.
Anna Rothschild: What happens?
Deepak Cyril D’Souza:Um, it can sometimes trigger mania. It can trigger depression. More hospitalizations, more ER visits, more nonadherence with medications that are helpful, more trouble with the law, more spending sprees and things like that.
Anna Rothschild: Do you think that cannabis is safe for people with anxiety or depression?
Deepak Cyril D’Souza: I suppose anything in limited amounts and in moderation might not be unsafe, let me put it that way. And truth be told that the overwhelming majority of people who use cannabis use it intermittently and small amounts of it and most of them don’t experience problems with it, right?
Just as with alcohol. But we know people, everyone knows someone who cannot handle their alcohol or has had bad experiences from alcohol and likewise, you know, the same would apply to cannabis. So there is some epidemiological data suggesting an increased risk of depression and suicide in adolescents who start using cannabis. Higher rates of that. And while most people use cannabis to relieve anxiety — to chill out, to relax — when it’s used repeatedly, and in some people for reasons we don’t understand, it can actually worsen anxiety.
Anna Rothschild: Cyril also said that using weed for anxiety can lead to dependence.
Deepak Cyril D’Souza: We know that while initially cannabis might relieve anxiety when taken in small doses and taken intermittently, if it is used on a very regular basis, there’s some degree of adaptation. And therefore, to derive the same amount of benefit or reduction in anxiety, a person is going to have to increase the amount of cannabis they use. And then it reaches a point where if they try to stop using cannabis, they will experience a withdrawal syndrome, which is not a pleasant syndrome.
Brooke Borel: So what about PTSD? That’s a common one that doctors are legally allowed to treat with cannabis, right?
Anna Rothschild: Yes, exactly. But just to set the stage, before we hear from Cyril, do you want to give us a quick definition?
Brooke Borel: Sure, I would love to. So post-traumatic stress disorder — this is a condition that can develop after a person experiences a traumatic event. And it can lead to flashbacks and nightmares. And patients can be really emotionally reactive when they have this, and they might avoid triggering situations.
Anna Rothschild: Yeah, exactly. Thank you, Brooke. Now let’s hear from Cyril.
Deepak Cyril D’Souza: There are anecdotal reports that cannabis helps symptoms of PTSD. However, when you do double-blind randomized placebo controlled studies, it shows that cannabis is no better than placebo. And in observational studies, epidemiological studies, it looks like people with PTSD who use cannabis generally have negative outcomes.
Anna Rothschild: Cyril also said that patients with PTSD might escalate their cannabis use, like he said about anxiety.
Deepak Cyril D’Souza: By the way, there is — I have had one previous indirect interaction with Matt Hill, maybe 10 years ago when the Canadian Broadcasting Company called me up and called him up and we were on the call together. And they had a Canadian veteran who claimed that cannabis was helping his PTSD. And we had opposing views about it at the time. So it’s coming like a full circle.
Anna Rothschild: Well, good to know that the two of you have not changed your views too much in a decade. Interesting.
Deepak Cyril D’Souza: I would like to say that the evidence has not changed. Not my view.
[Music]
Brooke Borel: You know, cannabis has been around for so long and people have been smoking it forever.
Anna Rothschild: True.
Brooke Borel: And I don’t know, I’m just really surprised at how limited the research is on how it may affect people’s mental health — especially when we are talking about serious mental health issues.
Anna Rothschild: I know. I know, it’s surprising, but also, these studies are really hard to do — and to do well. And with that limited evidence comes these really nuanced disagreements. So on that note are you ready to hear from Matt Hill?
Brooke Borel: Yes, let’s do it.
[Music]
Anna Rothschild: The question of the day is: Is cannabis ever safe for people with serious mental illness?
Matthew Hill: I do think there is some potential that cannabis products could provide some benefit for individuals with post-traumatic stress disorder, particularly with respect to their sleep, and possibly individuals with some forms of anxiety disorders.
Anna Rothschild: This is Matthew Hill. He’s a neuroscientist at the University of Calgary in Canada who studies the endocannabinoid system. That’s the biological system that THC and other compounds in weed interact with in our bodies. . And in particular, Matt studies the ways in which the endocannabinoid system regulates stress and anxiety. He mostly studies this in animals.
And to be clear, it’s not that he thinks that cannabis is safe for everyone who has serious mental illness. He agrees that cannabis is not safe for people with diagnosed schizophrenia or bipolar disorder. He just thinks there are some cases where it doesn’t hurt — and may even help.
Anna Rothschild: What does the data show about the usefulness of cannabis or THC on PTSD?
Matthew Hill: The saying I always have as a scientist is I say, a thousand anecdotes aren’t data. There’s still a thousand anecdotes, but if you don’t listen to a thousand anecdotes and think you can create a hypothesis out of that to test, then you’re also not being a very good scientist. The use of cannabis in the context of PTSD does go back quite some ways that precedes social media and precedes the internet, before people were kind of influencing each other the way they are now. And the consistency that would come out of a lot of these reports was very similar. And a lot of it relates to the sleep component.
Anna Rothschild: Many people with PTSD have altered REM sleep, which is when most of our dreaming happens. And it makes them prone to nightmares. The initial traumatic event that led to the PTSD can be reintroduced in this totally uncontrolled way. They’re just exposed to it again and again through the nightmare. But, at least anecdotally, cannabis can help.
Matthew Hill: If you actually look at what a lot of individuals with PTSD are saying, the majority almost always say what it does is it helps them go to sleep in a way where they don’t seem to have the nightmares the same way. And so they just tend to feel better and as a consequence of this, their quality of life improves.
I don’t believe anyone I’ve ever seen report this has ever said they find it cures the disease. They just have found it a very useful tool to help manage the sleep component of the disease, which often they find is some of the worst parts. And we all know if we’re not getting any sleep, no matter what we’re dealing with, it just gets worse and worse and worse and snowballs.
Anna Rothschild: What about the safety of it? You know, just because something might have a benefit, there could also be risks. So, is cannabis safe for people with PTSD?
Matthew Hill: A lot of it really depends on how the individual begins using the cannabis. So within Canada, through our veterans program, we actually do have subsidies for cannabis for war vets. And if you actually talk to — and I have talked to — a lot of the veterans in Canada who are under this program, who use it, the overwhelming majority of them have never escalated their use. And they’ve restricted their use of cannabis to a very small level, usually like half a gram, let’s say, of cannabis, that they would consume within an hour of going to bed.
And they have said, a lot of them — again, this is all anecdotal, but when they use it in this manner, they have found that it just consistently helps them sleep. And they don’t have violent nightmares and they feel better. So I would say in those situations potentially the harms are much reduced.
Anna Rothschild: That said, just like Cyril, Matt did warn that using it could be harmful if it becomes something patients do excessively.
Matthew Hill: Anxiety disorders, I think they’re a bit more of a challenge and I think that they deserve a little bit more conversation than just saying “no, I think that they have no value.” In terms of regular cannabis users, any of the survey data that’s been done, you know, 85-90 percent of the people, the number one response of why they use cannabis is because it reduces anxiety and stress.
And I feel like that should not be ignored. I mean, in fact, that’s been the basis of my entire scientific career. The endocannabinoid system is an incredibly important system in the brain and body in terms of stress buffering. We know that it gets mobilized in response to stress and it helps adaptation and recovery from stress.
I think the problem we see with something like anxiety, more often than not, relates to the escalation of use that emerges. You can imagine then if someone’s using cannabis chronically and that excess use of cannabis is probably burning out those receptors and burning out the endocannabinoid system and that may make you more vulnerable to developing anxiety or worsening your anxiety, which would then predicate greater use of cannabis to try and compensate for that.
Brooke Borel: Oh wow, yeah, so he’s basically saying that it can become a vicious cycle.
Anna Rothschild: Yeah, exactly. Which, I feel like is something I’ve observed in friends who smoke a lot of pot.
Brooke Borel: Sure.
Anna Rothschild: But it’s interesting that there’s data to sort of support that observation.
Brooke Borel: Yeah. So, another question though: Can we jump back to schizophrenia for a minute?
Anna Rothschild: Totally, yeah.
Brooke Borel: So, I know Matt doesn’t think people with schizophrenia should smoke pot. But I’m curious — does he think cannabis can cause schizophrenia?
Anna Rothschild: Well, let’s take a listen.
Matthew Hill: I don’t believe personally that the evidence would suggest that cannabis can cause schizophrenia if we’re defining cause as regardless of someone’s biological background or vulnerability or predispositions. Can cannabis act as a risk factor or bring out the disease or accelerate its onset or trigger a psychotic episode? Yes. I think there’s a substantial amount of evidence in that sense, that indicates that that is definitely the case. But there are many variables that can also contribute to the onset of schizophrenia.
Anna Rothschild: Matt explained that the first episode of schizophrenia that a person has is often sparked by stress. Deploying to a war zone, for example. Or even going off to college for the first time.
Matthew Hill: In that context, I think cannabis is one of the variables like these other ones that can lead to the development of a psychotic issue or of an episode and potentially bring out the disease possibly earlier than it would have manifested otherwise in the absence of cannabis use. But, to me that’s a different way of looking at something than to say that something outright causes it.
Anna Rothschild: One of the things that you’ve talked about in other interviews is how it’s possible that the reason that we see this correlation between cannabis use and schizophrenia is because people who have schizophrenia may be seeking out cannabis to deal with their symptoms in some way. Can you talk a little bit about that?
Matthew Hill: The rates of cannabis use in populations of individuals with schizophrenia is much higher than the general population. That’s also true of nicotine and to some degree alcohol, but definitely nicotine and cannabis are used at much higher rates in those populations. And there have been a lot of questions as to “Why is that the case?” And I would say it’s not clear. There are some studies that have suggested some of this could be a self medication approach. Other studies counter this and say they don’t find evidence for it.
Anna Rothschild: The studies that do suggest a self-medication approach find that patients use cannabis to help with symptoms like anxiety and social withdrawal, which typical schizophrenia medications don’t address.
Matthew Hill: There’s also some suggestion that individuals with schizophrenia may also find cannabis more rewarding than others. There’s definitely some data that does suggest that at a biological level, individuals who have schizophrenia may have different distributions of cannabinoid receptors in their brain. And so I think there’s definitely something there. I just — it’s hard for us to fully understand the nature of it. And so, I think we should understand the motivations behind why there’s higher rates of cannabis use in there that may give us some insight into why it is that an individual who’s using a substance that can actively make some of their symptoms worse is continuing to use it.
[Music]
Brooke Borel: So just to make sure I understand, is Matt saying there might be another thing going on here? That schizophrenia may lead people to use cannabis more?
Anna Rothschild: Right, though I want to be clear, he’s not necessarily contradicting Cyril here. He’s just bringing up what may be another piece of the puzzle.
Brooke Borel: I wonder what Cyril would say about that?
Anna Rothschild: Well, I had the chance to bring Matt and Cyril together and we talked about it.
Brooke Borel: Excellent.
[Music]
Deepak Cyril D’Souza: Is it the case that if you have schizophrenia, you’re just more likely to use cannabis? Or is it the case that if you use cannabis, you’re more likely to develop schizophrenia? I think there’s data that seems to go in both directions that perhaps they’re common risk factors for both cannabis use and schizophrenia that may be shared.
There’s experimental data, some of it from my lab and other labs, where we’ve been able to induce symptoms of psychosis in healthy individuals who don’t have any risk for psychosis. That said, very importantly, not everyone who uses cannabis develops schizophrenia, and not everyone who has schizophrenia has ever used cannabis. So, cannabis is neither necessary nor sufficient, but we think it may be a component cause interacting with other factors that we don’t fully understand. Factors such as genetic factors, and maybe early life, trauma, and things of that sort.
Anna Rothschild: Matt, I would love for you to respond.
Matthew Hill: I completely agree with Cyril in terms of his, the data from his lab, as well as others, as well as the ER data we’ve seen that certainly individuals who are not prone to develop schizophrenia can have acute psychotic reactions to cannabis. I don’t think anyone would disagree with that. That is probably the most robust adverse event that someone can have from consuming cannabis or a cannabis product, but also acute psychotic episodes do not necessarily relate to the development of schizophrenia as a disease per se.
Anna Rothschild: So, just to hammer home this point, what Matt is saying is that sometimes otherwise healthy people who use cannabis can have short-term psychotic episodes.
Brooke Borel: Oh my god. That’s a thing?
Anna Rothschild: Yes. It is not common.
Brooke Borel: OK.
Anna Rothschild: But it can happen.
Brooke Borel: OK.
Matthew Hill: Again, I don’t disagree that cannabis is one of a multifactorial thing that can influence the development of the disease.
Deepak Cyril D’Souza: Can I, I’d like to just follow up on a few things that Matt said. OK. I’m a psychiatrist and I treat people with serious mental illness. If I can identify one factor that is preventable, that may contribute to the onset of what is a lifelong terrifying illness, then I think that’s worthy of study and worthy of recognition.
And we can’t do anything about someone’s genetic risk for schizophrenia, at least at the present time. What we can do, just as we did with smoking and lung cancer — that is a preventable factor and if we can educate people about perhaps delaying their use of cannabis until their brain is fully developed, that’s worthy of pursuit.
And the second thing I wanted to mention: Matt said that there are people who experience psychotic reactions or episodes following the use of cannabis. There is now emerging data from especially the Scandinavian countries that if you look at people who had an index episode of cannabis induced psychosis — which is previously thought to be a very discrete syndrome. If you look at what happens to them in the next five to 10 years, depending on what definition you use, up to 50 percent of them are re-diagnosed with schizophrenia. Suggesting that if you experience an episode of cannabis induced psychosis, it could be considered a harbinger of a chronic recurrent psychotic disorder that, in our current nomenclature, we call schizophrenia.
Anna Rothschild: Just a quick fact check — it was actually up to 46 percent of patients, not 50. But the point is that what we today call a short-term condition may be a sign of schizophrenia.
Matthew Hill: I mean, I agree that it is important to educate the public on the risk. I mean, in Canada on cannabis products, one of the main warnings that’s listed is the increased risk of schizophrenia. And I think that was appropriate to include that the same way it is with cigarettes and lung cancer.
And again, the data linking, you know — certainly someone having had a psychotic reaction to cannabis and down the road developing schizophrenia, that’s been established here. We see that in Canada as well. We’ve seen that in the ER data. But again, I’m remiss to refer to that explicitly as causality because again, to me, that could just be a canary in the mine.
Brooke Borel: It seems like, to some extent, Matt and Cyril are simply having a semantic discussion, right? Like, they’re not exactly disagreeing on data, just whether or not to call it causality.
Anna Rothschild: Yeah, exactly. And I will say, I was a bit skeptical about why that distinction really matters. But then Matt said this.
Matthew Hill: The association with cannabis and schizophrenia was determined in periods of prohibition. So, prohibition doesn’t block that. But prohibition and having cannabis be illegal at a larger public level creates a lot more harms to society, particularly in the context of marginalized communities.
And that’s more where I take the position on this is just that I think that we need to be very careful with our wording because of the way that it gets manipulated by politicians to make an argument one way or the other, regardless of what the actual science is saying, and regardless of what your and my intentions are when we have a scientific debate about this.
Anna Rothschild: OK, let’s talk about PTSD. Matt, do you want to go first this time?
Matthew Hill: Sure. I think under certain conditions, in certain situations, that there could be some benefit of cannabinoids. Now, I would never suggest to someone off the bat that they start by trying cannabis. However, if someone is currently using sparing levels of cannabis to help themselves sleep and not have nightmares with post-traumatic stress disorder, I would probably not ever tell them they should have to stop. I would just encourage them to be very careful of their use patterns, so that they were mindful of not escalating their own use.
Anna Rothschild: Cyril?
Deepak Cyril D’Souza: I think that I would feel much more comfortable as a physician to see efficacy data from double-blind randomized placebo controlled studies that are well blinded and that are adequately powered.
Anna Rothschild: Here, Cyril mentioned a large double-blind randomized placebo-controlled trial he’s doing to look at the effect of cannabis on nerve pain.
Deepak Cyril D’Souza: I think that before we are able to recommend cannabis for PTSD, we need to do similar kinds of studies. So there may be certain symptoms of PTSD — sleep, for example, intrusive memories — that may be good targets for cannabis, but there may be other symptoms of PTSD that might actually get worse with cannabis. We really need to do research.
Anna Rothschild: Alright, I have one final question for you. So, you seem to agree on almost everything here.
Deepak Cyril D’Souza: Sorry, I’m really sorry about that.
Anna Rothschild: No, I mean, I think it’s lovely. I think it’s great. I think that what’s interesting, right, is that even though two scientists who ostensibly may have differences of opinion on some of these issues, they end up being mostly kind of semantic. But I think that in itself is interesting simply because of the way that these fights are brought into legal battles over legalization. And I’m curious, in a general way, do you feel like debates over the safety of cannabis on mental health are sort of manufactured? And do scientists just generally not disagree much on this subject? It’s politicians who are maybe misunderstanding data or skewing data in a way to, to make a point that’s more political versus scientific?
Matthew Hill: When we get into political theater and what we see when people debate is they kind of cherry pick these extreme opinions more often than not, and use them as if they’re, you know, founded evidence. And this is, you know, the reality of our modern world as we are learning day after day here, that the political differences of opinion can become so dramatic and really push people into opposite corners where they may be taking positions that they don’t inherently even necessarily agree with just because of where they stand.
Deepak Cyril D’Souza: Yeah, I agree with Matt. I think at least in the scientific community, people tend to be a little more careful in their positions and more willing to accept alternative views. I was a bit anxious about debating my colleague Professor Hill, but I’m glad it turned out this way.
And then your next question would be, would you take some cannabis before you have this radio show to treat your anxiety? No.
Matthew Hill: Yeah, I mean I do think sometimes people have a different perspective of where my positions may be. I mean, my favorite thing coming off of the Huberman thing was that I had emails from people telling me that I clearly knew nothing about cannabis and was super anti cannabis and like, how dare I say some of the things I say.
Then I had other people emailing me telling me, you know, “Oh, you’re such a cannabis advocate.” And I kind of thought, you know, if people can listen to this and half of them think I’m a cannabis prohibitionist and half of them think I’m an activist, then I probably did it right because no one can quite tell what my position is.
So I’m center of the road where I should be. So that made me feel good.
Deepak Cyril D’Souza: Well, look forward to meeting you at ACNPO.
Matthew Hill: See you in a few weeks in Phoenix, Cyril.
[Music]
Anna Rothschild: Alright, Brooke, what are you thinking now that you heard this quite agreeable conversation?
Brooke Borel: I know, they agreed so much. When we started out working on this I didn’t think that was going to be the case.
Anna Rothschild: And there may be scientists who are way more fringy, you kno, on either side of this debate. But I think this shows that a lot of the controversy is maybe manufactured and more politicized.
Brooke Borel: I mean, that makes sense. That happens all the time with science, right? People will take studies and take data and try to cherry pick it or twist it to match their political agenda. Should we ask what our listeners have to say about this one?
Anna Rothschild: Yes, please send us an email at entanglements@undark.org
Brooke Borel: And that’s it for this episode of Entanglements, brought to you by Undark magazine, which is published by the Knight Science Journalism Program at MIT. The show is fact checked by Undark deputy editor Jane Reza. Our production editor is Amanda Grennell, and Adriana Lacy is our audience engagement editor. Special thanks to our editor in chief, Tom Zeller Jr. I’m Brooke Borel.
H/T: undark.org
You can view the whole article at this link Podcast: Cannabis and Severe Mental Health Disorders
