Cannabis for Psychiatric Disorders? 'Not Today,' Experts Say

This transcript has been edited for clarity.

Stephen M. Strakowski, MD: Hello. Thank you all for joining us today. I'm very excited to have some great guests to talk about what I consider an active controversy. I'm Stephen M. Strakowski. I'm a professor and vice chair of psychiatry at Indiana University, and professor and associate vice president at University of Texas in Austin.

Today we're going to talk about cannabis. As all of you are aware, everyone's talking about cannabis. We hear constantly on social media and in interviews, particularly with relevance to psychiatric disorders, that everyone should be thinking about using cannabis. That seems to be the common conversation.

Last week, I had a patient who said, "All my friends tell me I need to be on cannabis." That was their solution to her problems. With that in mind, let me introduce our guests, who are both experts on this, to talk about the role of cannabis in psychiatric disorders today.

First, I want to welcome Dr Leslie Hulvershorn. Dr Hulvershorn is an associate professor and chair at Indiana University in Indianapolis. Dr Christopher Hammond is an assistant professor and the director of the co-occurring disorders program at Johns Hopkins. Welcome!

Leslie A. Hulvershorn, MD, MSc: Thank you.

Christopher J. Hammond, MD, PhD: Thank you.

Strakowski: Leslie, as I mentioned, many people are talking about how cannabis could be a good treatment for psychiatric disorders. Is that true?

Hulvershorn: If you look at what defines a good treatment, what you're looking for is clinical trials, ideally randomized, placebo-controlled clinical trials.

When we look at research related to cannabis, we see very few of those trials, and we see that the cannabis plant is actually quite complicated and there are many different compounds that come from it. So we need to look at all the different compounds.

If you think about THC, delta 9 or delta 8, depending on the version, that's the active ingredient that we most often think about when we say "cannabis." If you look at THC studies, there really is no evidence that I could find that it helps psychiatric disorders.

What we do find is an enormous literature, many hundreds of studies, actually, that show that THC actually worsens or even brings on psychiatric disorders. There's a separate conversation about other compounds within the cannabis plant, like CBD, cannabidiol, where there's maybe a signal that certain anxiety disorders might be improved by a compound like that.

Certainly, rare forms of epilepsy have been found to be improved with that compound. It really depends on what you're looking at within the cannabis plant, but if we're thinking about THC, the answer really is no, this is not a helpful thing. In fact, it's probably a harmful thing to be ingesting in terms of psychiatric disorders.

Strakowski: Thank you, Leslie. Chris, what would you add to that? Do we know anything about the use of cannabis in any psychiatric condition?

Hammond: I definitely would echo what Leslie said. The popular opinion, that the media and the state legislatures have really, in many ways, put the cart before the horse — they speak about cannabis as a medication for the treatment of psychiatric conditions before we have sufficient evidence to say that it's safe or effective for these conditions. Most of the evidence that we have, particularly in regard to the cannabinoid compound, delta 9, tetrahydrocannabinol, or THC, suggests that that cannabinoid is associated with adverse mental health outcomes across different categories.

Strakowski: Our group, a long time ago, conducted a study looking at first episode of mania, and found that regular cannabis use increases the risk for subsequent manic episodes. I'm not aware of many other studies like that.

You referred, Chris, to the safety aspect. If you look at social media, the press, and the conversations where cannabis is talked about, there's no risk, right? This is something anybody can use. There are no negative consequences. Is that true? I mean, is it really risk free?

Hammond: Research shows that that's an inaccurate framing of the safety profile of cannabis. Again, as Leslie put it very well, cannabis is many different compounds. Using this catchall phrase of "cannabis" is not very helpful.

In regard to the main bioactive compounds of the cannabis plant, THC and cannabidiol, or CBD, what we know from studies of THC administration and from medications that have been designed to mimic THC and act on receptors that THC acts on is that those medications have clear side effects and adverse events in a percentage of patients who take them, particularly in regard to precipitating panic attacks, dysphoric episodes, and psychosis in some individuals.

Hulvershorn: I would add that it really depends on the age of the person that you're talking about and when they're first exposed to cannabis. If you're talking about a person, say, under the age of 14 who uses cannabis, there's a large amount of concern about the worsening of psychosis and mental health symptoms, but also cognitive features like memory.

There's a very good study that was conducted in New Zealand that followed a large number of kids over time and showed significant decreases in working memory capacity for kids who used quite heavily.

Then you think about pregnant women. That's very interesting literature, where people are finding that cannabis not only affects brain development but also a host of other systems in the body. For example, I think the risk for asthma is increased. If you look at the genes in the placenta that are affected, it has much to do with the immune system.

Women who are using cannabis during pregnancy are really exposing their fetus to a range of potential risks that we certainly don't understand well enough, but there's enough science that suggests this is really concerning.

If you take a step back and look at animal models, even with things like CBD products, which, again, everybody seems to be buying and they're viewed as very safe — it's almost hard to find things without CBD these days.

There we find, for example, in developing rats that testicular development seems to be affected with high doses of CBD. There's just a huge array of effects, even outside of the psychiatric world, that make me very nervous about anyone using, especially a pregnant woman or a young person.

Then there's a whole separate literature on adults. It's hard to find studies that suggest this is a great idea. You're going to find on the mental health side of things, and the cognitive side of things, many effects as well.

I, personally, am agnostic one way or the other. If cannabis turns out to be helpful, great. We love things that are helpful in medicine. We don't really care where they come from. I'm not biased politically one way or the other. It's just when you look at the totality of the literature, it's hard to feel excited about people using cannabis at any age.

Hammond: It's difficult to interpret the literature because of some biases there. It speaks to the importance of thoughtful research being done in this space that takes a neutral approach to assessing cannabis and looking for evidence of both potential benefit and potential harm.

The other piece that I think is of value that builds off what Leslie mentioned is the effects of cannabis and THC. The risk for harm appears to be greater in pregnant women and in young people. For adults, I think, we're also still trying to understand what the effects are.

The other way of parsing out effects and thinking about them is in terms of the acute effects and the acute response in the moment right after one ingests cannabis vs the long-term effects.

After acute ingestion of cannabis, it can precipitate a psychotic episode, dysphoria or severe depressive symptoms, or severe anxiety, and can cause one to be disoriented, have delayed response time, and affect the ability to drive. In that capacity, it is related to a higher risk for motor vehicle crashes.

Strakowski: That's very interesting. In my practice, and maybe it's atypical, but half to two thirds of my patients, particularly the younger ones, are using cannabis in some form or another. In my experience, if they're under 21, they're more likely to use cannabis than alcohol.

What do we tell our patients? Is there a safe level of use? Do we say to never touch it? How do we manage the social pressure and environment that our patients have to live in?

Hulvershorn: I think about what we call motivational interviewing and the substance use disorder field, which is a style of interacting with someone that's very neutral to discuss the pros and the cons. In my practice, people are usually coming to us because of problems related to their substance use.

Not everyone is experiencing those, but for those people, it's a pretty easy discussion. It sounds like you're getting into trouble. Your athletic performance is suffering. Your scholastic performance is suffering.

You walk them toward understanding that, wait a minute, if I smoked less weed or no weed, I would probably be doing better in this or that domain of my life. That seems to be the most helpful thing, by allowing them to come to that conclusion.

I think it is a more difficult conversation for people who don't identify any problems related to their use. What is the right answer? Again, I just go back to saying, "Is this good for you? It's hard to find the literature that suggests that. Is it neutral for you? Maybe, for some people. Is it harmful for some people? Absolutely."

I think, for me, the most impactful studies have been those that showed for certain people with certain genetic makeup, cannabis is an absolutely terrible idea. Their risk for psychosis development and things like that are so high. For other people, they could smoke weed all day and never have a problem, based on their genetics — maybe. We don't know. It's not like we're doing blood tests to figure out who you are.

The safest advice, I think, is no use. That's never going to be bad advice.

Hammond: I mostly agree with Leslie on this point but feel very, very strongly that — in this era, where in the context of popular media, celebrities and other people are stating that cannabis is good and should be put in everything — clinical providers, especially pediatric providers, need to be extremely grounded in the science, and not let popular media sway our approach and strategy for working with these young people.

There's two decades worth of data from longitudinal studies that have followed individuals from birth or from preadolescence into their thirties and forties, that show us that, for this association between cannabis use and later adverse mental health outcomes, there is a dose effect there.

The earlier an individual starts using, the more frequent they use, and more persistent their use is over time, those individuals have poorer mental health outcomes compared with individuals who choose to abstain or individuals who use just a few times and stop.

There's also a signal for higher-THC-potency products being associated with poorer mental health outcomes, particularly when used during adolescence.

I apply a motivational interviewing approach as well to disseminate this information to both the young people and their parents about the risks, and to communicate what the data clearly show in regard to using THC-based cannabinoid products, which is that we don't have evidence that shows that any use is healthy to the developing brain.

There's a large amount of evidence that suggests it's harmful to the developing brain, so the recommendation is not to use, to delay the onset of use, if you want to use, until adulthood. Many youth choose to use. For those young people, we meet them where they're at and try to work with them on cutting down.

Strakowski: Thank you both. There's an interesting effort in different states, with lobbying by celebrities and legislators pushing insurance companies to fund cannabis use broadly, including in a number of psychiatric indications, with no FDA approval at this point. Do you support that? Is that a good idea?

Hammond: Absolutely not.

Strakowski: Thank you.

Hammond: I think that's a very important statement to make. For the medical and healthcare profession to stand strong related to states requiring insurance companies to cover medical cannabis really opens the door to lawsuits that would force insurance companies to cover other undertested bioactive chemicals and health supplements.

There are insufficient safety data for medical cannabis for FDA approval for any condition right now. The FDA has approved cannabinoid-based medications. Those cannabinoid-based medications have really undergone rigorous safety and efficacy testing, and have been approved for very narrow indications, none of which are psychiatric conditions.

They've been approved for chemotherapy-associated nausea and vomiting, treatment-resistant seizures related to two rare seizure disorders that emerge during childhood, and related to tuberous sclerosis, and one related to treating multiple sclerosis–associated spasticity and central neuropathic pain.

Hulvershorn: Steve, I think it's important for listeners to be aware that there is a process in place for any therapeutic to become tested and reviewed. We see an industry that stands to make an enormous amount of money, and that is really the motivation for this industry.

These are not folks who are, out of the kindness of their heart, just hoping for better treatments for people. There are many ways you could channel that desire that does not include cannabis making money.

It's really a profit-motivated industry. They're very effective at lobbying. The public, unfortunately, has been sort of manipulated by this industry to believe that these are healthy, safe, and natural just because they grow in the ground.

Unfortunately, that's really the issue. I think people just need to keep that in mind. Someone stands to make a large amount of money off of this. This is a very calculated, strategic approach that goes state by state but is nationally organized, and is potentially, like Chris says, for many reasons, really harmful.

I see it as sort of a bullying approach. Like if your drug works, Medicaid will pay for it. Medicaid in each state will review the studies. The FDA obviously leads the way. To cut the line without the research is really not helpful — circumventing the process that's been in place for a long time and works well.

Hammond: Yes, it sets a dangerous precedent.

Strakowski: I was going to add the same, that it's potentially dangerous. Thank you both, Drs Hulvershorn and Hammond, for a really good, lively discussion. I know we could talk for a very long time about this situation.

I do think it's clear for listeners, most of whom are practitioners, that at this point in time, there just really does not seem to be strong evidence for the use of cannabis-based products for any psychiatric condition.

I do think we have to approach the people we're working with around their psychiatric conditions to manage use and abuse wisely, like we would with any other substance. I appreciate everyone who's tuned in today to watch us. I hope this is useful for your practice. Thank you.

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