Why overdose may be the wrong word when it comes to cannabis

11 Sep 2018 | Canada
Why overdose may be the wrong word when it comes to cannabis

Whether or not you can overdose on cannabis depends on two things: how you ingest it and how you define the word "overdose."

For most people talking about illicit drugs, an overdose means someone died or had to be resuscitated.

Basically, this is what we've seen with the growing opioid crisis: take too much and you die.

A report released in May by Alberta Health Services found 733 people in the province died from accidental opioid overdoses last year.

An Alberta Health report found 355 people have died in the first half of this year, which means an average of two people dying every day in the province due to an opioid overdose.

But cannabis is quite different, as it's not actually possible to ingest a lethal dose.

You might get sick, paranoid or even pass out, but no recorded deaths anywhere in the world have been attributed to taking too much cannabis.

That's likely the cause of the intense outrage seen online and on social media in response to a recent CBC report on numbers released by the Canadian Institute for Health Information (CIHI).

The figures show that over the past three years the number of emergency room visits attributed to cannabis overdoses almost tripled in Ontario — going from 449 in 2013-14 to nearly 1,500 in 2017-18.

In Alberta, that number has nearly doubled over the same timeframe, from 431 to 832.

Fair to say overdose?
"Overdose is a bit of a crude term," said Dr. Eddy Lang, an emergency room doctor in Calgary.

He also serves as the zone clinical department head for emergency medicine at the University of Calgary and Alberta Health Services.

"We think of it in terms of opioids where, clearly, someone who has never taken opioids, if they take an excess amount, they will always get into trouble," Lang said. "It's not as cut and dry with cannabis."

If overdose isn't the correct term for taking too much cannabis, then what is?

One name gaining popularity is "greenout," which is when someone gets sick after smoking or eating cannabis.

Lang said it's preferable to use the term "self-poisoning."

"For the most part, poisoning is the function of two things. It's the toxin and the dose, and usually that's quite linear in that we can predictably see. As alcohol levels rise in the blood, people become more and more impaired to the point where it can become lethal," he said.

"Such a thing does not exist with cannabis. It's almost impossible, as far as I know, to ingest so much that you would lose consciousness or be unable to maintain your vital functions."

The AHS report released in May, titled Opioids and Substances of Misuse, also refers to deaths as "accidental poisonings." Lang points out that when someone ends up in an emergency room from drinking too much, that's called alcohol poisoning, rather than an alcohol overdose.

Matthew Hill, an associate professor at the Hotchkiss Brain Institute in Calgary, has studied the effect of endocannabinoids on the body, mainly as they pertain to anxiety and stress. He also says the term "overdose" isn't entirely applicable when referring to marijuana.

"You can, yes, quote-unquote overdose, but it depends on how you define overdose," he said.

"And the reason I say that is most people associate overdose with death, and that's not what the actual definition of the word should be."

Spike in cannabis overdoses blamed on potent edibles, poor public education
The definition of the word overdose should instead be that you consumed far more than you intended to and you had an adverse reaction to that, Hill said.

Usually a cannabis overdose would look like someone having an intense panic attack and, more rarely, an acute psychotic episode, he said.

Hill also took to social media, asking his followers and those in the medical community for their thoughts in the form of a poll.

Granted, a Twitter poll isn't exactly scientific, but Hill's found that "cannabis toxicity" was the favourite among four choices, with 398 people responding. "Cannabis overdose" was the second most popular choice.

Why you can't die from marijuana
It boils down to how the drugs affect our bodies, Hill said, and it's rather scientific.

"The reason you can't die from marijuana and the reason you die from opiates is because there's no cannabinoid receptors in your cardio-respiratory or pulmonary systems in the brain stem, and there are for opiate receptors," he said.

"When opiates bind there, they depress neural activity in the part of your brain that unconsciously regulates breathing and heart rate. So if you pass out, you stop breathing and your heart stops beating. There's no cannabinoid receptors in those brain regions in humans, so you can't physically overdose to a fatal level."

But just because you can't die from taking too much cannabis doesn't mean you can't overdo it. cbc