Psychiatry & Psychotherapy Podcast - Does Cannabis Use Increase Schizophrenia and Psychosis?

Episode Date: October 24, 2019

In this episode, David Puder, M.D., and Victoria Agee discuss possible links between marijuana use and psychosis. There a multiple studies which reveal links in genetics and marijuana potency that can lead to an increase in schizophrenia and psychosis.  Link to blog. Link to YouTube video.

Hello and welcome to the Psychiatry and Psychotherapy Podcast. I'm here to talk about getting rid of burnout, increasing job satisfaction, and feeling like an expert in what you do. One thing that created a lot of burnout and angst for me was trying to get continued medical education right at the last minute. So why not join the CME membership and do CMEE while listening to this podcast? Go to Psychiatrypodcast.com, sign up, sign in, take the test, and the certification is emailed to you in seconds. A couple years ago, I was struck by a patient who came in to my office. who was having psychotic symptoms. He was seeing spiders on the wall,

and he was punching them with his fists. He was having issues because the group home that he was living at was very upset that he was putting holes in walls. And when he talked to me, he said, there are these effing spiders, and they keep coming down at me at night. And, you know, no one believes me. And I'm not crazy.

And, you know, this is a guy who had started smoking marijuana when he was 13. He had some family history of psychosis. You know, I think it was his grandmother who had schizophrenia. And he was a fairly normal kid up into the age of, you know, his early 20s in which he had a psychotic break. He was a marijuana user. I don't know if the marijuana was related to the psychosis, but all of a sudden I started seeing more and more patients in the psychiatric hospital and in my practice where psychosis sometimes was preceded by marijuana use. So in this episode, I'm going to go into the details on

what might be the link between marijuana use, high potency marijuana use, and psychosis. And there are a lot of really good studies coming out, big studies, lots of people, multiple sites, studies where they look at the genetics of marijuana, where they look at, you know, like all the different genetic things that could increase psychosis. And does that have an additive effect if they also smoke marijuana daily?

A couple of things we'll talk about is the potency of marijuana increases the risk of psychosis. And the genetic factors actually do have a compounding influence to increase risk of psychosis in those who smoke marijuana. on a daily. So I hope you enjoy this episode. I am joined with Victoria A.G. She is a fourth year medical student here with me at Loma Linda. She's been on a rotation with me. We've been digging into some research and we will have all of these things in the resource library for you to look

at the actual citations to consider this question yourself. Take our assessment, but then also do your own consideration on what you think might be going on here. And as always, I'm open to any feedback. I'm open to any discussion on this on my social media channels. I'll be posting a link to this episode. And feel free to comment and put your thoughts, put your experiences. And if there's any studies that you think I'm missing, share those with me as well. All right. So welcome to the podcast. Thanks for having me back. And if you guys have any papers that you find that are recent, that, you know, you think could contribute to this or you have anything to add, you know, send them to us. So we can also look at them.

Yeah. We've tried to do our best looking at, you know, the articles up to, you know, like the past couple weeks, like what's been released. But I'm sure post this article more will be released. So please send them our way and we'll try to add it to future content. So a little bit of background. Tell me a little bit of background about cannabis, THC, psychosis, schizophrenia. Okay.

So when we were looking into this, I really kind of wanted to look into the background and see what really started this kind of research. And it was in the 1970s that researchers started looking into cannabis as a possible cause of psychosis. They started to ask if cannabis was responsible for short-term psychotic reaction or was it a trigger for a possible longer-lasting schizophrenia. So I was in the 1970s. In the 1980s, a man named Sven Andreessen looked at the Swedish population because cannabis was fairly pervasive during that time. And so he looked at a military conscript registry of about 45,000 Swedish men and found that about 4,300 of them used cannabis at least once. and he described frequent use of cannabis as 50 or more occasions and infrequent use as less than that. And based on his study, he was able to show a dose response relationship between cannabis and schizophrenia.

And importantly, of the 274 conscripts that had a diagnosis of schizophrenia at follow-up, only 21 of them were still frequent cannabis users, leading to the idea that cannabis might possibly be caused by emerging schizophrenia. and that schizophrenia can precede cannabis use. He also noted that it was important to know that schizophrenia can lie dormant in a person until they're exposed to a trigger like a psychoactive drug. So this leads to another idea that cannabis could have triggered this schizophrenia in a small population of vulnerable people within their sample.

Right. So this was his initial sort of thinking hypothesis ideas. and go on. So I think it's important to note here that just because there's a statistical association between cannabis and schizophrenia, that doesn't necessarily imply causation. So in the 1990s, they did further studies, but they found that it was difficult to compare study groups because there's no consistency in how cannabis consumption and potency had been measured. And it was in the 1990s that the DSM and ICD recognized cannabis psychosis as a,

a distinct diagnostic category. And then in 1998, man named Wayne Hall did a review on the two dominant hypotheses at the time. That heavy cannabis use causes a specific cannabis psychosis, and cannabis use precipitates schizophrenia and can make the symptoms worse. But he found a lack of controlled studies at that time. They were often compounding bias, and it was also hard to find people with schizophrenia who had only used cannabis as opposed to use cannabis as opposed to use. using cannabis and alcohol, which in and of itself also has psychogenic properties.

Yeah, that's really good. So that's some of the history. And now we'll be going into some of the most recent studies. So tell me about this Wenenberger 2019 study. Okay. So Wenenberger, I'm probably butchering his name, I'm sorry, or her name, did a study that looked at cannabis kind of prevalence in the United States, how it's changed, and what the daily use was like among people who had serious psychological distress versus people who didn't have

serious psychological distress, which will now be referring to as SPD, because that's a little bit of a mouthful. So they found that for cannabis use in the United States, approximately 25% of cannabis users use every day or nearly every day, which is a pretty significant increase over the last 10 years. And as the number of cannabis users increase, and it continues to be legalize, it's important to show what groups are at greatest risk to have these negative consequences. In April of this year, this study was published at the prevalence of cannabis use and people who did and did not have the serious psychological distress. And this was defined as worthlessness, hopelessness, sadness, or nervousness. So in 2008, the prevalence of cannabis

use among people with SPD was nearly two and a half times that among people without SPD. So they're saying that if you have serious psychological distress, you're twice as likely to use cannabis. So fast forward to 2016, people with past month SPD, or more than twice as likely to report daily cannabis use compared to people without SPD. Yeah. So I think this study in general just shows how both the rate of cannabis use has been increasing in the people without serious. psychological distress and in those with serious psychological distress. And so, you know, we know,

we know that people are commonly going to cannabis to provide them some relief. And it's a question of, okay, is the relief a temporary relief, or is the relief something that helps them over time? And so one of our arguments in our previous episode was that although it gives temporary relief, long-term relief is not something that we're seeing. We're actually seeing higher rates of depression, higher rates of suicidal thoughts, and so on. So let's jump to this Gobi 2019 article, which was a meta-analysis of 11 studies

comprising 23,000 individuals. And what did we find from that? And so from this article, like you had previously said, compared to young adults who didn't use cannabis, young adults who did use cannabis, had significant increases for rates of suicide aviation, suicide attempts with kind of like what you were saying. It kind of goes back to, does the cannabis mitigate these symptoms in the short term, but then really kind of increase the symptoms in the long term? and then are people trying to treat these symptoms with the cannabis use?

Yeah. So we're looking specifically at cannabis and psychosis. So are we any closer to understanding the relationship? And there's three hypotheses that we're going to be looking at and sort of diving into. So what are the three main hypotheses out there? Okay. So one of the big ones is cannabis can trigger schizophrenia. So we're thinking that if people use cannabis,

on a consistent basis, if they have similar genetics, similar environments, they are more likely to develop schizophrenia. Hypothesis number two. Cannabis can be used to mitigate the symptoms of schizophrenia, so reverse causation. I've heard a lot of people say that these studies can be invalid because, oh, there's higher rates of cannabis use among people with psychosis because they're using the cannabis to prevent their psychosis and to treat the symptoms. And then hypothesis number three is that there are.

some common external factors that account for the association. So childhood trauma, genetics, a pollution within the cannabis itself like heavy metals and pesticides, and that these all add to the fact that a patient could have schizophrenia. Yeah. So, you know, sometimes because something's correlated doesn't mean that it's correlated because of a specific reason or a cause, right? So in this sort of discussion and in this analysis that we're about to go into, we'll be going through some of these potential confounders and talking about, you know, what is the truth here and how do we sort of decipher what is the truth? And this is a, this is a really important thing that we try to do in psychiatry is we're just trying to find the truth. Like if I, if I got convinced that

marijuana was the cure for psychosis in a couple years, I'll change my mind and I'll start prescribing marijuana. And so here we are. We're trying to look at the evidence, and we're trying to just more closely approximate the evidence as we go on. Okay, let's talk about this one big study, DeForte 2019. This was done throughout 11 sites in Europe and Brazil. There were 901 patients with first episode psychosis across 11 sites, and there was a control that they did of a, 1,237 people at these same sites.

So they're looking at, you know, controlling for different factors, including like just general things like pollution and, you know, what people are exposed to in the environment and the city outside of, you know, having this psychotic event. And in this study, interesting, they looked at high potency cannabis versus low potency. So they define high potency as greater than 10% and low potency as less than 10%. percent. And we know in general that the potency of cannabis has gone up over time, you know, as people who are selling it find that they can sell more potent cannabis for more money.

They sort of try to genetically alter, you know, through breeding and stuff like that, strands of the highest potency to get higher potency over time. And that's been going on. And so in this study, they tried to look at that. And specifically, how did the high potency versus the low potency relate to the risk of psychosis. And as I was looking through this paper, we kind of wanted to find out, like, how did they figure out which was high potency and which was low potency?

And what they actually had the patients do is they would have the patients, in their own words, describe what strand of marijuana they used, where they got it from. And then the researchers went and looked to see what is the typical potency of this? strand that they typically buy. And that is how they defined it as the high potency or low potency. So they were using data that they already had based on specific strands to define that.

Yeah. So what were some of the main findings from this study? Okay. So main findings is that daily cannabis use was associated with increased odds of psychotic disorders compared with people who never used. And this was about three. 3.2 times higher. So that's huge. You know, significant P value, confidence interval 2.2 to 4.1. So somewhere around 3.2 times more likely to develop a psychotic disorder if they were daily cannabis users. Okay.

And what about if they were using high potency cannabis? So daily high potency cannabis use increase that's the odds ratio to 4.8. and that's with a CI of 2.5 to 6.3. So from just daily use to high potency use, that increased risk goes from three times to almost five times higher. I think that's really important too because they're both smoking marijuana daily.

And so you're controlling through that for things like, you know, heavy metals or pesticides or, you know, both cannabis is like, well, you know, both coming. and both being used on a daily basis in different cities across the world. Okay. So what, anything else that they found from this study? So they also found that if high potency cannabis were no longer available,

12.2% of the cases of first episode psychosis could have been prevented. And this actually increased in cities with higher prevalence. So London, it increased to 30%, and in Amsterdam it increased to 50%. So this is an estimate that they looked at. And think about that. Because Amsterdam has the highest potency cannabis, the rate of psychosis is higher. And the cause from the marijuana and the high potency marijuana is higher with that, right? So that's why they're estimating 50% of the cases could be prevented if there was no high potency cannabis. And that's, at least I think that's a crazy high percentage. It seems pretty high. One thing that I was blown away with in this paper is they said that some of the potency

goes up to like 63%. Yeah, like over 60% in some cities in Amsterdam. And this is coming from like the European like drug data that they get every year. Yeah. And we know, I know I talk to people in the chemical dependency unit here who are using wax, THC wax, which is like super high potency. So this stuff is being used more frequently. And what I've seen is that it definitely causes an effect on people

in a lot stronger way than those low potency, you know, options. Yeah. That, you know, have a much higher proportion of CBD can have a dial. Yeah. Anything, the graphs on this are worth a lot to look at. We'll put this in the handout in the resource library. Anything else you want to say about this study in particular? I think another big thing is that they looked at, obviously, you know, daily cannabis use, high potency, low potency.

But then they also broke it down into people who used cannabis, still like they started before they were 15 years old. And people who started after they were 15 years old. And they found that people who started using cannabis before the age of 15 baseline, had a 2.3 times higher risk of developing psychosis compared to the general population. Yeah, that's huge. And that's like, that's concerned because in the U.S., remember in that previous study we were showing,

the rate of cannabis has been going up. So the adolescent populations are really at risk for this. And I also notice in other sort of slides I've been looking at is that the younger groups are going up in specifically places where marijuana is being legalized. which, you know, take it for what it's worth, that's happening. You know, how is that happening? Well, if there's more marijuana readily available, people who are younger are going to be

able to get their hands on it. Yep. I also think it's important to note on this big DeF40 study that the patients they looked at were presenting with their first episode of psychosis, and this was identified by trained researchers. Patients had been excluded if they had previously been treated for psychosis, met criteria for some sort of organic psychosis, like a pathological effect, or if they had acute intoxication psychosis.

So the patients in this study had no previous psychosis whatsoever, which I think is important to note, especially because people are saying, oh, they're using cannabis to treat their psychosis. These patients had never had any psychosis before. First episode psychosis admitted to a psychiatric hospital and not using substances to invoke the psychosis. So that's that like, you know,

we see a lot of psychosis in our hospital from methamphetamines, from drugs. We see a lot from, you know, people who are chronically schizophrenic. It's a lot more rare to see a first episode. I would say maybe one in like 100 in the psychiatric hospital, just kind of like a rough estimate.

I mean, that's my own estimate. And that's why the N, you know, 901 was significant. That's a lot of people. And that's 11 sites, which is really a nice study. And that's, you know, 11 sites across Europe and including Brazil. So they have a nice, broad range of people to choose from. Okay. Let's go through some of the responses to this. So Gillespie at all 2019. What did he say? So Gillespie's main critique of the article stated that the harmful effects of high potency cannabis on mental health was likely overestimated due to the lack of adjustment for confounding from genetic environmental factors.

Gillespie actually did their own meta-analysis that resulted in a statistically significant genetic correlation between schizophrenia risk and risk factors for cannabis. However, their study didn't account for cannabis frequency or cannabis potency. And I think that's really important. we want to look at the potency specifically, and that seems to be really important to me. And the frequency of use, like daily use made it much bigger impact than infrequent use for the promotion of psychosis. Okay. And then Leanman, 2019, had a critique of it saying that other environmental co-founding factors, such as air pollution in Europe, specifically nitric oxide, had been shown in increased psychosis. which I don't know if that makes sense

just because it seems like they pick their controls from the same cities. And then there was another critique, Clark 2019, who stated that they did not test the purity of the cannabis to test for heavy metals, which is something we'll get to later in this topic. But could it be that schizophrenia is related more to the heavy metals?

that are put into cannabis to make the weight of the cannabis more. If it's heavier, then maybe you can sell it for more. But that didn't seem to really make sense in my mind based on the potency specifically. It seems like the more potent marijuana strands and the places of higher potency, like Amsterdam, had much higher rates of psychosis. So any other rebuttals that DeForte had in this?

Okay. So, Forte's rebuttal to this is saying that, again, they mentioned that in cities with the highest prevalence, that there's a large portion of the psychotic episodes that could have been prevented if the high potency had been taken away. And they also point out that, yes, like tobacco and pollution can have an effect on the psychosis. However, that was controlled and they actually looked at tobacco use. and alcohol use, and they found that it didn't make a difference on the psychosis prevalence and the increased risk for that. And they did actually say that if they did see an effect of tobacco driving the odds ratio, this was driven in part by cities in Spain and Italy where smoking was much more prevalent, both in the cases and the controls. So the proportions of smokers in Madrid, Malonia, Italy, were done.

double that of Amsterdam and in London. So that would greatly drive up the odds ratio and related to tobacco in that instance. I think the important in this is when you look at a study, do the control, does the control group and the study group under consideration have similarities? Are they well matched? Are they well matched? And this is very important when you're doing research. Are they matched for age, ethnicity, smoking?

alcohol use, some of these other factors. And that really allows you to sort of not get these confounders as much. Yeah. And also it's nice that it was multiple cities, right? Because that reduces other confounders about the cities that are unique. So, okay, let's jump to another study, Marconi, 2016. This was in a meta-analysis of 18 studies, including 60. 6,000 individuals, and it gave an odds ratio of 3.9 for the risk of schizophrenia and other

psychosis-related outcomes among the heaviest cannabis users compared to non-users. Anything else you want to highlight from this study? I think what's important to note is that this study very much correlates with the previous study that we just talked about, right? So they're saying that there, yes, there is a much higher odds ratio for people who use cannabis more frequently and with higher potency. So we're getting these big studies that continue to show very similar outcomes here. And, you know, there are some graphs that, again, will be in the reference materials that really kind of show the differences between all the studies.

But regardless of the study, all of them show an increased risk of psychosis, this increased risk of psychotic symptoms. Great, yeah. So there's a really nice graph where it shows, you know, as the cannabis exposure increases, there's this increase in the odds ratio. And if you look at multiple, multiple studies in this thing, you know, it's this nice curve that shows that as the cannabis exposure goes up,

in all the studies, they're finding the odds ratio of schizophrenia gets up higher and higher. Okay. Okay. So let's jump to genetic vulnerabilities to psychosis. So in general, we know that identical twins have higher rates of schizophrenia than fraternal twins or, you know, children. So for example, identical twins, same genetic material at birth, same womb environment, which is also important. If one of the identical twins has schizophrenia, there's a 48% chance that the other twin will also develop schizophrenia. So it's not, you know, it's not as high as height or some of the other things that are like much higher than that, but it's still 48%. That's significant. That's still pretty high.

If you consider 48%, you know, in the general population, it's 1%. About 1% develop schizophrenia. So one question I get sometimes from people is like if one of my parents has schizophrenia, how likely is it that one of the children will get it? And that's about like what, 6%. So it's not 48% and 6%. So there's some risk, some increased risk, but absolute risk is still pretty low. Okay, tell me, let's talk about this byoshi 2019. article, and they were looking at a specific gene called, it's a fatty acid amide hydrolase,

and what did they find with that specific polymorphism and how it related to psychosis and marijuana use? Okay. So they looked at 15 specific SNPs or single nucleotide polymorphisms within the endocannabinoid system and then their interactions with cannabis. and they found this specific polymorphism. I could read out all the numbers, but it's not going to mean anything to anyone,

but it's in the reference. But they found a specific polymorphism in an enzyme ligand that is associated with increased risk of first episode psychosis in patients with frequent cannabis use, but not in patients without a history of cannabis use. And it was found that patients who are homozygous dominant for this polymorphism was 10 times more likely to present with first episode psychosis with cannabis use.

Yeah, so this study was really interesting because the people who had this homozygous mutation, meaning they had some damage to this fatty acid amide hydrolyse would only have increased odds like 10 times higher. They're 11 times, almost 11 times higher. Only if they smoked marijuana. If they didn't, it wouldn't increase their risk of developing psychosis at all. If they didn't have this specific mutation, they would never develop it. Yeah.

Okay. In another study by Neiman in 2016, they were looking at the C-O-M-T gene, which is the catacolomethyl transfereous gene, and that gene breaks down dopamine in the frontal lobe. So if you have a gene that, you know, a certain variant of this, you have a higher rate of breaking down dopamine. It's better at breaking down dopamine. And what they found was that if you smoked and had this gene that the COMT gene, that was homozygous, and so you were breaking down dopamine faster and you had cannabis use. With that, you had an increased risk of developing a potential for increased psychosis in the future. So unless people know that they have this specific

variant of their COMT enzyme, they would never know they'd be at an increased risk. So if you ask your drug dealer for genetic testing before you keep smoking weed, that's that's pretty much the summary. Yes. It's basically in full. informed consent, you know, we had to give you the pros and the cons of the medication. Yeah. So, you know, and this is, this is an interest point. Like, of course, no one's going to get genetically tested for this stuff. Although maybe in the future, you know, every baby will have genetic testing in. And then they'll say, like, things that you are at higher risk of developing issues with, and on that list will be smoking marijuana and psychosis. And so maybe this will start

to help build that. Okay, let's keep going. There's another study by Missyak, 2017, and what did that study show? So again, this continued to look at genes and environmental factors for the development of schizophrenia and bipolar. And so they looked at specific protein kinase gene, and they found that people with a homozygous polymorphism with a history of cannabis use showed a two times higher risk of having psychosis in comparison to a different homozygous allelic trait. So basically if you had what they're calling a CC homozygous genotype, you're going to have a higher risk than compared to a TT homozygous genotype of this protein kinase. So among daily cannabis users, people who had this specific genotype, had a sevenfold increase in the odds of developing psychosis compared to those who had this other

genotype. So once again, this is showing that there are some patients who, you know, specifically are at higher risk if they have certain genotypes. And the problem is, is that we're not going to know who's at higher risk because of the genotypes. Like unless you, like you said, go and get your whole genome mapped out, you wouldn't know. Yeah. But then again, like, how would you, like, there's probably thousands of these genes that we just haven't found. So, okay. Where do you want to go from here? Okay.

So with all this said, like you're saying, there's thousands of genes that contribute to psychosis. But even with all that, like, genetic-oriented research has failed to provide a 100% certain plausible explanation involving biology and genetic factor. and cannabis and schizophrenia. Wait, wait. Okay, so sometimes I hear from like the pop media or whatever, like some doctor who doesn't quite know what they're talking about. They'll say something like, you know, there are no markers to any DSM diagnoses and biological, like, things that predicted, you know? And when I read that, I'm like, I don't think you've read very much. I don't think they've read at all. I don't think they've read at all because it's not that there aren't biological studies linking mental illness with like genetics and stuff.

It's just that there's a lot. It's complex. There's so many and there's finding new things all the time. All the time. Like within months, there'll always be another paper that comes out that shows, hey, we found this linking it to cannabis use and this. Yeah. And so this next study that we're going to go through is probably one of the most elegant studies on this that I've read. Yeah, it's nice. It's a great study.

You should read the study. And why I like this study is because they're looking at all the genes that put someone at a risk for any sort of psychotic disorder. So, and then basically they put people in the percentile of like, okay, do you have 75 percent? like they put people in like a bell curve of having like okay all the genes that we know that relate to some sort of psychotic illness and we're going to put people in the bell curve and then so if you are in the 75th percent hour above we're going to put you in a group now and that is what they did and then they looked at that and that group that's in the higher risk group and they looked at all sorts of factors yeah all sorts of environmental factors things like child child abuse or a history of child abuse, neglect, sexual abuse, bullying, emotional abuse, and cannabis use. So they're looking at all these emotional factors. And so you can learn a lot about psychosis from this. Yeah. Okay. So what were the big findings from this study? Okay. So kind of he said they looked at the big environmental factors in addition to the genetic factors. and this is looking at 1,700 patients.

So it's a lot of patients. They looked at additive interactions between all these environmental factors. So the additive interaction between their baseline genetic risk and cannabis use, cannabis had an additive factor of 5.6. This is compared to emotional abuse

with 5.2. And sexual abuse had the highest additive factor of 7.6. Okay, what this is saying is that there's genetic factors, like the people who are above that 75th percentile of having those genes, you take those people and then you put on other risk factors that we know about, like smoking marijuana, emotional abuse, sexual abuse. You put those things on top of that and it increases the risk of developing psychosis even more. So it's like there's risk with just smoking marijuana daily.

And there's also an additive, you know, there's an increased risk of schizophrenia with some of these other childhood issues, right? And then when you put them together, there's like an additive increase in the risk. And you have to see the graph to really understand like what this looks like. It's hard to explain it. But the basic idea is that it's both the. environment, it's the genes, and then it's the choice of does this person continue to smoke marijuana daily? And all of those things contribute to the risk of developing that first episode of psychosis. Yeah. So of the environmental factors that they looked at, sexual abuse had the highest

additive effect for risk of schizophrenia with 7.6, followed by regular cannabis use at 5.6, and emotional abuse at 5.52. Childhood bullying and emotional neglect were also statistically significant, but they were much lower. So basically they're saying if you are above the 75th percentile of risk factors with genetic markers for schizophrenia, and then you add factors like cannabis use, emotional abuse, sexual abuse, on top of that, baseline genetic risk, you're at much higher risk of developing psychosis. So once again, check out this picture, check out the graph. It'll make a lot more sense to you if this was confusing at all.

In this next section, we'll be going into some of the other sort of arguments against the idea that it's the cannabis that's causing the psychosis. We're going to be talking about heavy metals, pesticides, and more. So tell me a little bit about heavy metals in cannabis. Okay. So one of the complaints of that big study, the big deforty study, they were talking about the possible pollutants that can be in marijuana. And one of them that was brought up was heavy metals in cannabis.

And unfortunately, there are very few studies that actually show the effects of cannabis contamination. In regards to heavy metals, there are three ways that heavy metals can be introduced into the cannabis plant. So it's through absorption in the soil, through somehow when they're processing, or through post-production. And like you said earlier, it's known that heavy metals are sometimes added to marijuana to increase the weight and increase the street value. So as of 2018, there are 95 reported cases of lead poisoning. due to contamination of these illegal preparations. So basically they're adding these heavy metals to make them heavier. So that way you think you're getting one weight of marijuana,

but you're getting the weight of marijuana plus the heavy metals. Yeah. And that's really sad because, you know, people who get the marijuana of the street, you know, don't know if there are these heavy metals in. And one of the things that's interesting is that as we legalize the marijuana, they're testing this kind of thing. And in states where marijuana is legal, some of these studies have been done, right?

So in places like Amsterdam, marijuana has been legal for a long time. I don't know how regulated it is, but this is, you know, one of the things that is an additive risk. You know, is there lead in your weed? Well, and then even, you know, in the states that have marijuana legalized, yes, there are guidelines for cultivation and production, but cannabis is still regulated differently state by state. There's not this overall mandate on how marijuana needs to be produced, how it needs to be regulated, and the purity of it. Yeah. What about pesticides and cannabis? Okay, so people always talk about pesticides on their food, whether it's, you know, you're going to the grocery store and you're worried about pesticides getting, you know, on your fruit or in this case, same.

You know, you're worried about possible pesticides in cannabis. And, you know, they're supposed to screen for that when these legal cannabis dispensaries. Dispensaries. Thank you. Send in samples. they're supposed to screen for that. But there was actually a study done, and they looked at 26 samples of legalized cannabis products from Washington. And 85% of those products contain significant quantities of pesticides,

including insecticides, fungicides, miticides, and herbicides. 85% still had significant quantities of these pesticides. I had a patient recently who told me that he could tell when there were, pesticides on weed that was given to them. And, you know, more and more people are growing their own in these legalized states for this reason, I think, because they can control what is in them. Anything else on the pesticide sort of argument or... Sure. I have more stuff.

Okay. Okay. So there was an informal survey done in 2014, and that was done in California, and that showed a one to two percent incidence of... pesticide use. There was an informal survey in 2014 of California labs, and that showed a 1 to 2% incidence of pesticides. There was another study that was done where they contacted the California labs, and there was observed that anywhere from 15 to 35% of the samples that were submitted were actually positive, but those labs were hesitant to publicize that data because they were worried that such information could lead to unscrupulous growers seeking out more toxic agents

that weren't included in the labs themselves. So adding a pesticide that the lab didn't check for or adding some other sort of toxin that the lab didn't check for. And then in 2015, another survey of California demonstrated the presence of eight different pesticides in 33% of the samples, the most common being Paclobutrizo and that's a pesticide that's not registered with the environmental protection agency

for use on food crops. The other pesticides were biphtrin and microbutanil. Yeah, the more I read about these pesticides, the more I want to do a deep dive in a future episode.

But, you know, one of my thoughts is pesticides are, you know, a lot of these things are on fruit as well, like strawberries and, you know, things that, things that we would eat. And so one of my questions is like, you know, how much more is on the weed than is on some of the fruits that we eat or some of the normal foods? So is it really that much more? And is the, you know, smoking it, getting it into the lungs is that much worse than the eating it, which we do commonly and how much is really bad. These are really good questions. And if anyone is an expert and listens to this and has some

good papers, send them over. Yeah, let us know because there's not a lot of papers out there right now. And I think it's important to note that, yes, there are contaminants in the marijuana. Like, we are worried about that. But nowhere have we seen a study that linked these contaminants to psychosis. Yeah, so more to be revealed. And also, I think going back to that prior study about the potency, of the marijuana. I don't think it's only the people who are selling the highest THC content marijuana that are using pesticides. I think it's probably more evenly distributed, but, you know, that would be just kind of my reflections on it. So it doesn't make sense that, you know, only the high potency marijuana strands would have high pesticide content. Okay, what other types of

arguments have been put out there? So the other thought is that patients are using cannabis to combat their symptoms. You know, it's something that we've heard, you know, several times. And then although it's plausible, it should be stressed that there are actually several studies out there that show that this isn't the main reason that these individuals consistently give as their motivation to use cannabis. Their motivation to use cannabis, they say, is still kind of the main reason for the general population, just pleasure and recreation. They don't use it to combat their symptoms. Okay. Wow.

We'll bring this to a close. I hope this episode has been helpful for clearing up this difficult sort of research question is does cannabis cause psychosis and schizophrenia? I think most studies at this point point towards yes, it does, and that higher potency strands do more so. And further, there's a bunch of studies that are very elegant in showing that There are genetic things that can even further increase the risk of developing psychosis with marijuana use. And, you know, people who have a risk of developing schizophrenia because of some of those genetic markers, if they smoke, it puts them at even higher risk.

And so that's where I'm leaving it. That's what I believe at this point. I think it's a really good clinical question that we have to ask ourselves with is what is the best way of reducing the amount that people smoke or, you know, the patients that do smoke, how do we help them get off? I think that's a very difficult thing. But the first thing to do is to clearly understand what is the truth here, right? To make sure that people are informed of the risks that they are exposing themselves to when they use marijuana. Like I said earlier, Like when you give a medication, you always go over the pros and cons of the medication.

When you go through a surgical procedure, you go through the risks and the benefits and the other options. You know, it's informed consent. And I think that, you know, people who don't know the risks, they can't be informed. Yeah. And coming back to, you know, the actual people that we're seeing. You know, the actual people that we're seeing in the psychiatric hospital who are psychotic, it really does change your life forever. It really is an incredibly scary disease,

to have the paranoia, to have the loss of knowing what is real and what is not real and to be stuck in that state and to have an ongoing need for medications and support. These are very difficult, difficult things to treat, things to walk through. And our hope would be that through this podcast and through this episode, you would be a little bit more equipped to

educate the public, to educate your patients on the risks of developing psychosis in people who smoke and smoke heavily and specifically who smoke high potency marijuana strands. I agree.