Steven Fenster, neurobiologist and associate professor of biology at Fort Lewis College, gave a recent talk about the science behind marijuana’s effects on your brain. Following this student lecture, given as part of Animas Hall’s “Welcome to your Life” series, Fenster gave DGO the lowdown on the difference between compounds THC and CBD (the two main ingredients of marijuana), why weed is stronger now than ever and just how much cannabis really changes the inner workings of your noggin.
We know about the short-term effects of cannabis. Has there been research about the long-term effects, or is that ongoing? They’re difficult studies to do, but there is some emerging evidence, at least in adolescents, that heavy and chronic cannabis use can change the brain. They’ve started to advance the brain imaging study field; now they use a technique called Functional MRI which allows real-time imaging of the brain to see what happens when people ingest cannabis. Thinking back to my own childhood, I knew kids who were using cannabis at ages 12 and 13, and that’s a really critical age for brain development. From age 12 to 16, the brain is very sensitive to the effects of these drugs. It’s not until the age of 20 or so that our brains have reached their maximum maturity – not that brain cells can’t change, but in terms of growth.
Some studies have shown that people who are heavy users have lower IQ scores. But for those surveys, you have to ask a bunch of teenagers whether they’re using pot or not, which is always going to be difficult. And if you’re a heavy user in high school, you’re less likely to finish your high school education and get your degree. But there’s just not a lot of long-term studies looking at the effects of marijuana.
Can marijuana bring out dormant mental illnesses in people who are already genetically predisposed? When you talk about cannabis, you’re actually talking about a plant that has hundreds of different types of substances in it. The two that are the most well-studied are THC and CBD or “cannabidiol.” There is some evidence THC can lead to psychosis in certain individuals, and that includes paranoia, schizophrenia, maybe even depression. You’re putting THC into your body, it’s interacting and perhaps interfering with the neuronal processes in your brain. They’ve actually looked at people who have the classic type of schizophrenic episode – and this happens to people usually between the ages of 18 and 29 years old. Those who end up having these psychotic episodes as a result of marijuana, their behavior is a little different. They seem to be able to socially adjust to that kind of psychosis more, whether it’s an altered sense of reality or depression. They don’t have as severe disorders as someone who might’ve had it from some other trigger or type of development. So there’s definitely evidence to indicate that THC may be a compound causing that type of psychosis. At least that’s what we think! There’s many different kinds of compounds in cannabis that we don’t even necessarily know about.
People are critical about marijuana being classified as a Schedule I drug, like heroin. Is it as dangerous as all that, or mislabeled? I’m of the opinion that it’s mislabeled. The use of marijuana doesn’t correlate well with its classification. It’s an old one, the whole idea from the ’50s and ’60s of “reefer madness.” The caveat to that is that we have seen in the past 20 years the content of THC has dramatically increased in marijuana strains. Growers have identified strains with a higher content, then bred those strains. Strains with a high content of THC have a decrease in the other active compound, the cannabidiol. And there’s evidence to indicate that you need a balance between THC and cannabidiol in order to mitigate those potential psychosis effects. If you look at Europe, where marijuana is more of a hashish, that tends to have a better ratio of THC versus CBD. But the problem is, people want the really good stuff, the stuff that’s going to get you stoned, and of course the growers will respond to that. We have seen in the United States alone that the average THC content back in the late ’80s was less than 3.4 percent overall in cannabis strains. But by 2014, we’ve seen it increase to greater than 12 percent. That’s four times as much! I’m not for or against marijuana legalization. I think there are a lot of benefits. But what people need to understand is the marijuana you buy now in Colorado, or that you buy illegally in another state, has a much higher content than your dad’s marijuana. And if it’s high content, it could potentially have negative effects like psychosis, it could be more additive and it could affect a young person’s brain development. It’s not like if you go to the liquor store and buy a bottle of Jim Beam, and you know exactly how much alcohol is in that whiskey. As far as I know, a lot of the dispensaries are getting better at trying to put that information on the label now; my students who frequent the shops say they will put the THC content on there sometimes.
If cannabis is legalized in more states, will funding for research be easier? Trying to get funding from the federal government now? Forget it. It’s a Schedule I drug. But I hope so. We just had a change in the presidential administration, so I don’t know what Donald Trump will do. With Obama, he hasn’t changed it, though he’s alluded to the fact that he would’ve. My feeling, given the conservative nature of Congress right now, is that’s not going to happen for the next four years. Of course, they support alcohol and pain killer use, all this other stuff that’s probably way worse for your body. Marijuana has never been shown to kill anybody, though it is an addictive substance. About 10 percent of users become addicted in some form. But it’s less harmful than pain killers or opioids. There can be some symptoms of withdrawal, but way less. Even if you’re just a casual alcohol user, if you tell a doctor you drink two beers a day, they’ll watch you for withdrawal symptoms. People still need to understand any type of substance that provides pleasure, if you overdo it, you can become addicted.
What about positive medical benefits? There is evidence to indicate that cannabis can, in some instances, reduce chronic pain. That’s one of the reasons we’ve had more states approve medical marijuana use. It’s less addictive than pain killers. Another good thing that’s happening in this state is there are clinical trials using CBD to treat certain severe forms of epilepsy. “Charlotte’s Web” is a strain of marijuana bred with a very low content of THC and a high content of CBD. There was a doctor in Denver who got approval to use this on a little girl named Charlotte who had a severe form of epilepsy. She was having hundreds of seizures a day, and it reduced them to one or two per week. CBD doesn’t get you high, it doesn’t seem to have much of a psychotic or euphoric effect. They’re in the process of doing more trials now, and a lot of this is preliminary data. There’s still a lot of research to be done about cannabis with brain development, addiction, psychosis, pain management. Hopefully at some point in time, it’s not a Schedule I.
This interview has been edited and condensed for space and clarity. Anya Jaremko-GreenwoldDGO Staff Writer
