Recreational marijuana became legal in Vermont on July 1, 2018. What do we know about the positive and negative effects of cannabis in the body and the brain?
In the following interview, Peter Jackson, MD, and Karen Lounsbury, PhD, discuss the safety of marijuana. Jackson is a pediatric psychiatrist at the UVM Medical Center and assistant professor at the Larner College of Medicine at UVM. Lounsbury, PhD, is a professor of pharmacology at the Larner College of Medicine at UVM.
You can also listen to the full interview podcast below.
Is cannabis safe to consume?
Karen Lounsbury: “Safe to consume” is a relative factor, because cannabis has many effects in both the brain and in the rest of the body. Some of those effects can be potentially useful as medicines. The toxicity of the drug itself is relatively low. An overdose doesn’t cause as many problems as other drugs, like opioids, for example; however, it does have some risks with chronic use, and the adolescent population is especially vulnerable.
Peter Jackson: My perspective is often skewed toward the younger population. So, when I’m asked that by children and adolescents, my initial answer is no, it’s not a good idea to consume it. But, there are so many different chemical constituents of the cannabis plant, so it depends on what we’re talking about. As we learn more, we will see what parts of this could be helpful and what parts could be more harmful. It’s not safe to smoke anything, and so I often warn my patients about that.
What happens when cannabis interacts with the body?
Karen Lounsbury: You have an endocannabinoid system where your body can make endogenous chemicals, which are chemicals that your body makes itself. The reason why we have responses to marijuana is because we have receptors that are already enabled to be interacted with by our endogenous chemicals. These are released in response to high stress, things like pain, and also released in response to certain rewards. You have receptors that bind to these chemicals that reduce pain and reduce muscle spasticity, but also strongly affect the brain in terms of euphoria, strong memory and impaired driving.
There are many chemical compounds found within the cannabis plant. When they’re combined together, they make a medicine that relieves pain. This medicine causes reduced muscle spasms, and affects the brain in useful ways. It was tested and approved for use in post-traumatic stress disorder, for example. When used chronically and heavily, especially by young people, there’s a risk of addiction. That’s what we all worry about, because addictive disorders can lead to a variety of biologic and psychological problems.
How does cannabis affect the mind?
Peter Jackson: The cannabis plant contains more than 400 different chemicals. When you ask people what the experience is in their mind, you get a lot of different answers. Some people report feelings of euphoria and elevated mood. Some people find relaxation. Others experience more negative mental effects of cannabis. Those can include fear, paranoia, increased anxiety, and even psychotic symptoms. What we’re learning over time is that different constituents within the plant itself are responsible for these different effects.
Some initial research suggests that THC may be the compound that’s more “psychoactive,” and that CBD, cannabidiol, is the compound that may — from a cognitive or emotional standpoint — have more of the pleasurable side effects, and may be more beneficial.
How do you talk to patients about cannabis use?
The first thing that I want to know when I sit down with patients is their experience. I want to understand the reasons why they’ve used cannabis. I find out what they find beneficial. Then, I build off of that and find out if there are other means to achieve those outcomes that don’t come with potential associated risks. I’m often weighing the pros and cons of their use. If they’re asking for my opinions about it, I tell them about what we’ve learned in research so far. Often I’m meeting with a younger patient population. Research shows us differences in youth compared to adults as far as the risks and benefits of cannabis use on mental health.
How do adults and youth react differently?
Peter Jackson: The associations are, unfortunately, more negative with early use, particularly from an emotional wellness standpoint. When cannabis use starts early, we see a worsened onset and a prolonged and worsened course of most mental health challenges. So, association with a higher risk of anxiety, higher risk of depression, higher risk of psychosis. Research is still ongoing in that area, and we’re learning a lot more. So, we don’t know necessarily about causality, but we’re looking at associations. Whereas in adulthood, where the brain is more fully developed, the associations tend to be not quite as negative across the board for things like anxiety, in particular.
What is the difference between use and abuse?
Karen Lounsbury: Even though the adolescent population is more at risk for the negative associations with problems with memory, motivation, psychiatric issues, higher anxiety, potential depression, there are some instances where use in young people of not just CBD, but also whole plant marijuana or components that include THC, is beneficial.
It’s similar to how somebody might prescribe an opioid, for example. If you take it how it’s directed, you have good pain relief. If you abuse it, you have a high risk of addiction. The same problem happens with cannabis. There are certain beneficial uses: You can use cannabidiol, which is the non-psychoactive component, for seizure disorders in children. Cerebral palsy and multiple sclerosis may find benefit with whole plant cannabis, where the CBD compound isn’t as effective as other whole plant or THC-containing compounds.
Smoking is not healthy for the lungs no matter what. But, there are other ways to take cannabis or components of cannabis, like cannabidiol, without smoking it. There aren’t enough studies to know what the appropriate doses are. We don’t know what the strain of cannabis that’s going to be the best for a particular disorder is. And that’s where we’d like to see more research.
What research is taking place in your lab?
Karen Lounsbury: Right now we’re looking at cannabidiol and medical cannabis in oncology, for the development of peripheral neuropathy. That’s pain and tingling after taking chemotherapy drugs.
Is cannabis an alternative to opiates?
Karen Lounsbury: There have been several studies in the last couple of years that show a significant decrease in the amount of opioid use in patients that are using cannabis as an adjunct pain therapy. That said, we are looking at two addicting medications. A lot of care must go into how patients are going to be prescribed these types of regimens. And because we don’t have the appropriate laws for good counseling, right now it runs into a lot of issues with whether you would actually promote the use of cannabis in patients that are using opioids.
What are your concerns for youth?
Peter Jackson: My perceptions as a child and adolescent psychiatrist and an addiction psychiatrist, is about the vulnerabilities in the younger population and what that means for future in our communities.
We know that adolescents are much more likely to develop a problematic pattern of use of cannabis if they begin earlier. The earlier that someone is beginning to use something recreationally, the higher likelihood there is for a substance use disorder. So at least quadruple the risk, if not further increasing the risk, if you begin using in your teenage years compared to later adulthood.
We have a lot of studies that show us that up to one in six adolescents who start using will develop problematic use. One thing that we know pretty clearly is that the willingness of adolescents to use substances is inversely correlated with how dangerous or how safe that they think a substance is. So that’s one concern about legalization and we’ve seen that if teenagers feel that it’s safe, they’ll use more. That’s across the board for all categories of substances.
I think the same is concerning as far as parents go. We joke that parents have no control over teenagers, or they only care about what their friends think. That’s actually not true. Parents remain the strongest influence on their children’s behavior, and I worry at times that parents will have a misperception about the use of cannabis.
Karen Lounsbury: I would like to also agree with that. We look at the rate of addiction disorder for cannabis is around, officially around 9%. Which, when there’s a small percentage of the population using cannabis, that seems like a relatively small risk. However, once legalization occurs, you have that many more potential patients developing addiction disorders.
What happens to the teenage brain on cannabis?
Peter Jackson: There’s a lot of really interesting and fascinating science behind that. Teenage brains are not half-baked adult brains; they’re not broken brains. They’re just really exciting and fascinating brains that are in stages of change that are happening much more rapidly and in a much more plastic way compared to an adult brain. So you can imagine the neural pathways in a teenage brain like a road, and those roads are going from clunky dirt roads with potholes in them to becoming light-rail pathways. And so whatever is used and reinforced in adolescence, you have a lot more impact on neural pathways and connections in adolescent exposures than you do in adult exposures.
Karen Lounsbury: It’s interesting that the area of the brain that’s a little underdeveloped in the adolescent years, the frontal cortex, is the area of the brain that has the highest concentration of receptors for THC, your CB1 receptors. Because those receptors are there, it inhibits that area of the brain, because when the THC binds to those receptors, it inhibits the neurons. So, it’s almost as if adolescent use is even more exacerbated because they remove that action in an area that’s underdeveloped. That’s why they seek out those types of euphoric drugs that reduce that area of the brain, but at the same time it puts them at even more risk for addiction.