NEW ORLEANS – Marijuana and psychosis don’t mix, according to Erica Rapp, MD, an assistant professor of psychiatry at the University of Colorado Anschutz Medical Campus, Aurora.
Regular use is associated with increased positive psychotic symptoms, a wide-range of poor psycho-social outcomes, reduced medication adherence, and a higher rate of relapse that’s not entirely explained by reduced adherence. One study even found an increased risk of suicide, she said at the American Psychiatric Association’s Institute on Psychiatric Services meeting.
Dr. Erica Rapp
Epidemiological studies, meanwhile, have found a “robust” association between regular marijuana use and an increased risk of schizophrenia, about two-times higher in the general population and about four-times higher in people who are predisposed to psychosis. It’s possible that marijuana doesn’t actually increase the rate of psychotic disorders, but just makes them come on sooner. “While that is almost certainly true, it doesn’t exclude the overall increased risk,” Dr. Rapp said.
Researchers are working to unravel the cross-talk between marijuana and psychosis. It seems that with heavy, regular use, you “are basically loading your brain with dopamine; [perhaps] people become more sensitized to dopamine-induced perceptual and cognitive problems,” she said.
“Luckily, if we can get people to stop use early in the course of their psychotic illness, they do much better. There are improvements in mood, anxiety, positive psychotic symptoms, medication adherence, and global functioning,” she said.
It’s not easy to get people to stop, however.
The notion of “marijuana as a potent cause of schizophrenia ... is something that users do not like to hear.” Many consider marijuana “a medicine, and that if they smoke it, they are going to be healthier. If you suggest that” marijuana might do “some bad things in addition to all the great things they think it’s doing, they immediately think you are a narc, and shut down. It’s hard to have an open conversion,” Dr. Rapp said.
At this point, it seems that it’s the tetrahydrocannabinol (THC) in marijuana that causes problems for people who have or who are prone to psychosis, and that it’s the cannabidiol (CBD) component that’s responsible for the therapeutic effects. CBD appears to be a dopamine D2 receptor antagonist, and some small pilot studies have found anti-psychotic effects. “CBD actually has some potential as a treatment” for psychosis, especially for negative symptoms, she said.
So, when abstinence isn’t an option, “I try to steer people towards CBD, rather than THC. Labels in dispensaries tell you what the THC and CBD content are. Those can be really unreliable, but it’s something.” Staff can point out high CBD products. “I also usually caution against smoking. I tell people that smoking anything has bad effects on your health,” she said. Edibles are among the many alternative formulations.
Patients who are truly interested in therapeutic benefits appreciate the message. “If they say, ‘oh, that doesn’t sound like fun,’ it tells me they are really looking for the psychoactive THC high,” she said.
Dr. Rapp did not have any industry disclosures.