The myths and realities of cannabis

Because it is legal doesn’t mean it’s benign — doctors offer some advice

This week recreational cannabis became legal. Medicinal cannabis has been legal since 2001 and the number of medical users has skyrocketed, but they are still a tiny minority of the more than 3 million people who use cannabis. Legalization follows an increasing number of U.S. states, but, as the world’s 10th largest economy and the first G7 nation, this is a tectonic shift in drug policy.

While much will change, what won’t change are the risks associated with using cannabis. Here are some of the most commonly held myths.

• No. 1: Cannabis is largely harmless.

Not true. There are well-established risks of cannabis use, such as impaired motor coordination that can lead to car crashes or other accidents, chronic bronchitis from smoke exposure, and increased risk of psychotic disorders, such as schizophrenia.

Just because it’s legal doesn’t mean it’s safe. Governments legalize potentially harmful psychoactive drugs, like tobacco or alcohol, to offset potentially worse consequences of consumers accessing these products illegally. In these situations, legalization provides benefits — regulated production, quality/safety standards, accurate product labelling, and controlled distribution — that are intended outweigh the harms.

Finally, legalization is intended to permit law enforcement to focus its resources on more significant harms than personal use (e.g., illegal trafficking, distribution to minors) and divert revenue away from criminal organizations. Cannabis legalization has nothing to do with the drug being accepted as benign.

• No. 2: Cannabis is not addictive. Also false. Cannabis is an addictive drug and cannabis use disorder (addiction to cannabis) is an accepted psychiatric diagnosis. It is true that the rates of addiction are lower than for a number of other drugs, both legal and illegal. However, lifetime estimates for Canada and the U.S., tell us that between 1-in-20 and 1-in-10 individuals will develop cannabis use disorder, prevalence rates that are far from trivial. Importantly, these rates have been trending upward, perhaps because the amount of the chemical most responsible for the drug’s high and addiction potential, THC, has been increasing over time.

• No. 3: Cannabis isn’t physically addictive.

Wrong. Cannabis can be both psychologically and physically addictive. Extensive evidence has confirmed that, like most psychoactive drugs, the frequent use of cannabis leads to adaptive changes in the brain. This, in turn, leads to physical dependence on cannabis to sustain equilibrium. These adaptations then lead to tolerance, a reduced responsiveness to the same dose. Moreover, because the brain and body have adapted to the frequent presence of cannabis, physical dependence also means that stopping the drug leads to withdrawal symptoms, including irritability, anxiety, depression, headache, insomnia and physical symptoms, such as abdominal pain, fever, chills and tremors.

• No. 4: You can’t overdose on cannabis.

Not true. While you can’t suffer a fatal overdose with cannabis, consuming large amounts can absolutely lead to severe negative consequences. Cannabis-induced delirium, triggered by large doses, causes extreme disorientation and confusion. Excessive consumption can even trigger psychotic symptoms, such as hallucinations and paranoia. These symptoms can be very significant, requiring care at an emergency department or even a psychiatric hospitalization.

• No. 5: Cannabis is healthier than other drugs because it’s natural.

Incorrect. Just because cannabis is a plant, not a pill or another mass manufactured product, there is no reason to think it is somehow safer than other drugs. Almost all psychoactive drugs originate from plants. Tobacco, cocaine, psilocybin mushrooms, opium, morphine and heroin are all directly or indirectly derived from plants. In legal markets, cannabis brands are actively promoted as “natural” or “organic.” That’s good marketing, but bad science.

The bottom line is that although cannabis is not as dangerous as some other drugs, it is still a psychoactive substance that has real risks. We’re not trying to “harsh” anyone’s “mellow,” but as legalization takes effect across Canada, the public should be aware of the facts (and fictions) about cannabis.

Dr. James MacKillop is the director of the Peter Boris Centre for Addictions Research and the Michael G. De Groote Centre for Medicinal Cannabis Research at McMaster University and St. Joseph’s Healthcare. Dr. Jason Busse is the associate director of the Michael G. De Groote Centre for Medicinal Cannabis Research. Dr. Catharine Munn is a faculty affiliate of the Boris and DeGroote Centres, and is the lead psychiatrist at the Student Wellness Centre at McMaster University