Tuesday, March 8, 2011 | Categories: Dr. Brian's Blog
Like a car crash, many of us have been absorbed watching as actor Charlie Sheen descends into a sad spectacle of madness and drug abuse. Earlier this week, we learned from that august web site TMZ.com that a species of pot has been named after the putatively insane actor. Click here to get the scoop from TMZ.
Canada has one of the highest rates of marijuana use in the world. According to a 2007 report by the United Nations, nearly 17% of Canadians between the ages of 15 and 64 smoke pot or ingest one of its derivatives. Many people think of cannabis as a harmless drug. Now, a new study may change that view.
Researchers from the Netherlands, Germany, Switzerland and the UK found a side effect of using marijuana that should give parents pause for concern. The study - which was published in the British Medical Journal - tracked more than 1,900 young people age 14 to 24 over a period of 10 years. Researchers found that 13 percent of the participants reported using cannabis at least five times at some point during their lives. That figure rose to 20 percent by the three and half year mark of the study. They concluded that those teens and young adults who use cannabis were nearly twice as likely to exhibit psychotic behaviour at some point compared to those who didn't use the substance.
Other studies have found an association between psychotic behaviour and marijuana use. This study was the first to demonstrate that marijuana use precedes the onset of psychotic symptoms. The researchers excluded anyone who reported cannabis use or pre-existing psychotic symptoms prior to the start of the study. The study controlled for factors like social status or wealth and the use of other illicit drugs like crystal methamphetamine and cocaine - factors that independently increase the risk of psychosis - as well as other psychiatric conditions (for example, depression).
The bottom line is that cannabis use significantly increased the risk of psychotic symptoms like hearing voices - especially voices telling the person to do something to harm themselves or others. What's more, the greater the number of times subjects used marijuana during the course of the study, the greater the risk of psychosis and the intensity of psychotic symptoms.
The big unanswered question from this study is whether the use of marijuana caused psychosis or unmasked a pre-existing tendency.
In my work as an ER physician, I'm seeing younger patients - teens and young adults - who come in feeling agitated. They may have been found at a bar or at a party acting aggressive. Often, they're brought in by police and need six or seven grown adults to restrain them. They talk about receiving messages from deities or being followed. In the past, I would automatically certify them under the Mental Health Act and send them to the psychiatrist for an assessment. But now, sometimes, I just keep them in the ER overnight. And when the effects wear off, they're back to normal - calm and collected. Often, they're reflective about the fact they were acting strange.
I'm often asked whether there's something about today's marijuana bought and sold on the street. Marijuana has long been known to have psychosis-inducing properties. A study found that both marijuana and ketamine - a club drug known as 'special K' that we use in the ER to sedate patients (including children) having broken bones set - can induce psychotic symptoms. So that's nothing new. However, I have certainly heard psychiatrists and drug abuse experts say that there's something different about the marijuana that people can buy off the street. They think it's more chemically pure and stronger than what was sold twenty or thirty years ago. It's entirely possible that today's marijuana is laced with illicit drugs like ketamine or crystal methamphetamine.
Medical marijuana is no different from marijuana used for recreational purposes. THC - the active ingredient in marijuana -- can cause psychotic symptoms whether it's used for one purpose or another. However, there are three reasons why we seldom see patients who use medical marijuana developing symptoms of psychosis. First, medical marijuana is often taken in pill form. It may well be that marijuana that's smoked produces more profound psychotic effects because it activates receptors in the brain more quickly. Second, medical marijuana is of more consistent potency and quality than the cannabis that's bought and sold on the street. Third, the people who use medical marijuana are older than the age at which symptoms of psychosis first appear. One is very unlikely to see a patient having a first psychotic break due to schizophrenia in the forties or fifties. However, it's possible that an older patient in the early stages of dementia might be at risk of psychotic symptoms were they to try medical marijuana.
This study demonstrated that the risk of persistent psychotic episodes increases with longer periods of cannabis exposure. Young people who experiment with cannabis need to be told about the risk of using it. At the same time, when I see young people in the ER who have a psychotic episode that turns out to be due to marijuana, maybe I need to tell the patient and the family that it could be a warning symptom of a psychosis disorder like schizophrenia down the road. If that's the case, maybe we should be telling people like that never to use marijuana again.
Are Charlie Sheen's problems the result of smoking dope? That would be the tamest explanation by far!