Students aren’t getting the facts about marijuana

Research shows links to mental illness, lung capacity


Photo by Yeshe on Flickr

When sociologist and drug-policy expert Andy Hathaway surveyed one of his first-year classes at the University of Guelph last fall, 80 per cent of students reported experience with cannabis.

Hathaway cautions that it was only a small pilot study (around 100 responses), and it took place at Guelph, which is, let’s face it, “a bit granola.”

Still, that 80 per cent figure isn’t surprising.

When twelfth graders are asked if they’ve tried marijuana, roughly half say yes.

Provincial rates of lifetime usage now range from a low of 40 per cent of Albertan twelfth-graders to a high of 63 per cent of those in Nova Scotia, according to the Canadian Centre on Substance Abuse. And that’s before university.

Smoking pot can’t be considered deviant anymore, says Hathaway. It’s simply the new normal.

A loosening of cultural attitudes, particularly in the media, helps explains the shift. “We had Cheech and Chong in the 1970s, but that was a very stereotypical portrayal,” says Hathaway. “Now we have shows like Weeds that show use of marijuana by very regular people—soccer moms and dads.”

But as attitudes toward marijuana soften, some campus health experts report that they’re more worried about students using the drug than ever. That’s because research increasingly shows links between marijuana and the number one health problem on Canadian campuses: mental illness.

Dr. Elizabeth Osuch, a psychiatrist who runs the First Episode Mood and Anxiety Program at a hospital in London, Ont., encounters mentally ill students who offer their own evidence of marijuana-related problems. “I hear the story frequently about how ‘I get paranoid when I smoke pot’, ‘I get anxious when I smoke pot’, or ‘I’ve been smoking pot a long time and now I’m depressed’,” she says.

That’s not surprising to Dr. Osuch. What’s surprising to her is how surprising that is to others.

“I’ve given talks across this community and when I talk about the effects of marijuana, it’s news to people,” she says, “unless I’m talking to a group of clinicians who interact with people in a medical or counselling setting. They know, because they’ve been seeing this for years.”

The best-established risk is that marijuana can trigger or exacerbate psychosis in a small number of people who are susceptible, based on their genes. To some, the link is not even debatable. “A number of prospective epidemiological studies put it beyond doubt that cannabis use increases the subsequent risk of schizophrenia,” wrote the authors of a 2007 review in Addictive Disorders.

Devastating as psychosis may be for those who experience it, diseases like schizophrenia only affect a small proportion of the population. But Dr. Osuch warns that marijuana may also be contributing to the most common health problems on Canadian campuses: depression and anxiety.

One study published in Drug and Alcohol Dependence in 2007 followed a group of 14 to 17-year-olds over a decade, checking up on their mental health and drug use along the way. They found that depression, bipolar disorder and, to a lesser extent, anxiety disorders, all coincided with previous cannabis use—and more use predicted more illness.

But that’s only the beginning. “I would predict that there will be more and more information out there in the coming years looking at the problematic effects of what’s no longer a ‘soft drug’,” says Dr. Osuch, who notes that there’s more Tetrahydrocannabinol (THC) in in marijuana today than ever.

Dr. Osuch is currently the lead researcher on one such study exploring the links to depression. She explains the theory behind that possible link: “Marijuana is very active on the neurocirciutry of reward processing. Anything that you do because you like doing it activates reward processing in the brain,” she says. “And if you slam that neurological system daily with a chemical [like THC], it becomes very difficult for the person to feel reward from doing normal things,” she adds.

Dr. Osuch is quick to point out that not everyone who smokes pot will have a problem. “But a significant percentage of them will,” she says, adding, “as long as you know what those percentages are, or a sense of what the risks are, you can make an intelligent decision.”

Right now, the students she meets when giving talks at the Western University in or London, Ont. high schools haven’t gotten the message. They perceive pot-smoking as low risk.

Part of the confusion is the conflicting messages young people get when they type “marijuana health effects” into Google. “What they’re getting is all kind of sites that say marijuana is great,” says Dr. Osuch, “what they aren’t getting is the scientific research.”

There are, of course, some well-funded and easy-to-find meassages about the risks online—those from the federal government. But Hathaway, the drug policy researcher at Guelph, says the federal government’s anti-drug messages aren’t trusted by youth, because they exaggerate the risk.

In one of the federal ads, called Fast Forward, a blonde boy refuses a puff on a joint after he envisions a life of violence and trouble with the law. In another ad, called Mirror, a girl in her bedroom ends up cutting her arm with a piece of glass after taking some unidentified drugs.

Such scare tactics cause teens to tune out drug messaging entirely, says Hathaway. “If you’re sending inaccurate messages about marijuana when they have enough experience to know this is basically propaganda, they’re going to have doubts about any message of that kind,” he explains.

Although Hathaway doesn’t advocate abstinence like Dr. Osuch, he does believe there’s room for better education about marijuana. “Effective social policy would account for the small minority who may run into trouble with drugs and be candidates for some kind of intervention,” says Hathaway.

The government might do better to educate youth about the dangers of smoking tobacco along with marijuana, for example, says Hathaway. Tobacco is known to reduce lung capacity and increase the risk of cancer. Meanwhile, a study in the Journal of the American Medical Association in January showed that smoking two to three joints actually increases lung capacity.

But because the JAMA article portrays marijuana as less harmful, it’s unlikely to would make it into the government’s messaging. Once again, the science is unlikely to reach young Canadians.

And if there’s one thing Dr. Osuch and Prof. Hathaway agree on, it’s that young people need better access to the facts. That way, they can determine the risks for themselves—whatever they may be.


Students aren’t getting the facts about marijuana

  1. From my experience, university students who ‘indulge’ in cannabis (the real name for marijuana), are more likely to have a broader world view (not restricted by conservatism) and understand just how screwed the world is. This in turn results in depression and anxiety. The prescription, zonk-out the students with pharmaceutical cocktails to blind them to life’s reality. Instead they should prescribe counselling and stress/anxiety management.

  2. Actually, the problem that the prohibitionists are having but refuse to acknowledge is that youth is getting the facts about cannabis. The facts are not the bald faced lies, half truths, and hysterical rhetoric promoted by the prohibitionists. Even worse, when junior figures out that you’re lying to him about cannabis his adolescent mind almost inevitably jumps to the conclusion that the prohibitionists are lying to him about other things which are genuinely deleterious to a person’s well being.

    The twaddle about cannabis causing mental illness is so easy to disprove that it’s mind boggling that this particular canard keeps getting trotted out. The Rastafari have been using cannabis as a sacrament since at least 1930 yet their rate of psychoses is in line with that of the general population. The rate of psychoses did not increase during the 1960s despite an increase of more than 1000% in the incidence of people choosing to enjoy cannabis. It is beyond absurd to claim that the incidence of a causal factor for anything could increase 1000% without a corresponding increase in that which it allegedly causes.

    If you want youth to take you seriously, you’re going to have to quit lying to them. It takes about 5 minutes inside of my world to figure out that the propaganda against cannabis is nothing but hysterical rhetoric.

  3. Dr. Elizabeth Ousch is the lead researcher ?

    We are fucked…

    Considering most “Pro-Pot” sites have nothing but links to “Scientific Evidence.” Uses multiple sources….

    BTW… Smoking pot increases lung capacity, it doesn’t decrease it.

  4. Yes we are; we’re just not believing the lies anymore.

  5. Psychiatric studies have been subject to all sorts of social bias. Throughout the 20th century, American Psychiatric Association viewed homosexuality as a mental illness and approved the cruel use of lobotomies on tens of thousands of mental health patients (including alcoholics and other drug addicts).

    It’s clear that the vast majority of drug-induced “psychosis” that harms both individual and society is caused by alcohol. However, alcohol and its extremely negative effects on our society have become so normalized in our culture that not even psychiatrists (many of them drinkers) bother to label these tendencies towards violence, recklessness and promiscuity as alcohol-induced “psychosis.” In fact, a psychiatrist would become the laughingstock of the world if they published a study saying that people who drink experience “psychosis” earlier than non-users and that such symptoms may lead to developing a permanent mental illness later in life.

  6. These “studies” that link pot use to mental illness are as bunk as the government’s mine shaft weed. All the corporate media are falling in line with King Harper’s wishes in advance of his mandaTORY prison for pot users bill clearing the senate. There is is no reason to continue the harm-maximization approach that is prohibition. Consider that groups like the partnership for a drug free-(insert country name here) are largely funded by alcohol and pharmaceutical companies. Anyone think they might be interested in keeping their state enforced monopoly on conciousness alteration? Alcohol and legal pharma products kill many thousands of people per year. Pot has never killed ONE! Try asking psychiatrists if there is any link between alcohol use and depression or anxiety, or about the effects of alcohol on triggering pre-existing mental illness and you will find out that alcohol is MUCH more likely, in fact almost guaranteed to cause problems for the mentally ill. We don’t hear anyone suggesting that we criminalize alcohol though do we?

  7. “young people need better access to the facts.”

    No they don’t. If anything, they might benefit from better critical thinking skills and some instruction on how to tell science from
    pseudoscience, both of which they have far better access to than any generation before them. A good BS detection kit would also benefit those who, for whatever reason,choose to abstain.

  8. These doctors are putting the horse before the cart of mental illness. Saying that there is a correlation between cannabis and mental health issues. this is fine…I guess, it is a beautifully crafted argument because it is left to cannabis advocates to either attempt to prove a negative, an impossible task, or to attempt to ignore the argument, whereby the anti-pot advocates can point and say “look, they can’t answer you on this issue therefore pot is bad.”
    The only logical way to discover the link between cannabis and mental health problems is to actually give pot to a large number of people of all types and under controlled conditions, take a clip board and count how many developed these mental health problems. This is obviously morally…what’s the word?…wrong. So how are they coming to this at all?
    Follow the money.
    The logical fallacies that the government and pharmaceutical companies are employing, is going to shine a bright light on to their corruption when they are forced to say that it is a plant with a lot of helpful uses and a wide range of applications. When this happens, the people who consider themselves the power elite, the law makers, will be forced to admit to illegally detaining citizens and causing untold millions of dollars in damages against the population they swore to protect. In fact the only reason they are allowed to make such laws is because we, the citizens of the world, allow these people the right to force their views on us.
    Ladies and Gents, this is just the tiny tip of a much, much larger issue.
    From one journalist to another…check your facts, or check who signs your pay checks and decide if you are the type of person who is okay with putting harmful ideas out into the world.

  9. ” They found that depression, bipolar disorder and, to a lesser extent, anxiety disorders, all coincided with previous cannabis use—and more use predicted more illness.”
    Which came first? Perhaps the Illness led to self medication….

  10. Articles like this and the one on retirement are examples of why I’m mot renewing my subscription to your magazine. I’ll continue to recieve information from sources that have a modicum of research.
    Step away from the bar and call a cab.

  11. It’s funny that they always seem to find the exact same targets when they want to demonize…the exact same targets.

    They never worry about the toxic chemicals in the food supply. Those toxic chemicals are all 100% safe.

    They never worry about the toxic chemicals from the pharmacy, because those toxic chemicals are “legal.” (And disgustingly profitable for their corporate criminal friends.)

    They don’t worry about the toxic chemicals in the water supply. Again, those toxins are added to make the water supply safer…so those toxins are also 100% safe.

    Finally, they never bother to let anyone know about the bioacculmulation of toxins in the human body that we receive from the air, water, and food supplies. After all, bioaccumulation of known toxins has been shown to be perfectly safe…for corporate bottom lines.

    It’s time to stop demonizing a plant with propaganda which continually proves that the plant is not only far less of a problem than politicians make it out to be, but that it may be one of the few options we have left to restore the climate, repair our soil, and eliminate our reliance on petrochemicals.

    Of course, “reality” isn’t something that politicians care about these days…they care about making sure that the corporations who pay them off get their money’s worth…no matter who it hurts.

  12. What everyone seems to not realize is that drugs have changed over the years and drug dealing is a business like any other. The dealers wish to increase their business and thus take the measures to do so. Not only are the drugs stronger than the 60’s to 80’s but they are most often laced with highly addictive substances, ie: Crack, cocaine etc. Speak to those that are involved everyday with this… the police. I am so glad I went to a public speech put on by the police when my oldest was in grade 3 that is where they gave me the facts on drugs! They know the strength and what they are finding in the drugs today and just exactly what the world is dealing with overall.

    They will tell you that drugs today are very dangerous just as the author of this article has pointed out, but what the author fails to speak about is that the drugs are not the same as years past and thus because the drugs are not “clean”, they are both extremely dangerous and highly addictive. You don’t even know what it is you are smoking anymore. This might be the reason their are a higher percentage of Psychosis of those doing drugs.

    This may be why there is a movement to legalize marijuana, although I am not an advocate of that because I can see many problems down the road with this if you look at the full picture.

    Drugs today are scary and I would warn anyone to stay away, as I have seen first hand with some of my friends kids that have chosen this path, they seem to be on a path of self destruction because of the addiction they have developed. I am so sad for them and would encourage any and all kids to just stay away from drugs period!!!

  13. Concerned parent, if you really want to know the truth about cannabis and other drugs in order to protect your children, the last thing you should do is talk to the police, unless they are members of LEAF – Law Enforcement Against Prohibition. I suggest you go to their website to see what honest law enforcement members have to say about prohibition.

    You will only get propaganda, like the DARE program, from police departments that have a financial interest in boosting their budgets by perpetuating the war on some drugs. They tell lies about cannabis to frighten citizens, just as fear-mongering politicians like Harper do, who wants to build more prisons even though the crime rate is falling.

    You also only get propaganda in this Maclean’s article. It is completely biased, only citing weak studies that support the article’s thesis, while ignoring strong studies that undermine that thesis. It is true that young people need to be informed with the facts about cannabis, but they need to be informed about all the facts, not just selective facts by propagandists. A couple good places to start are the following websites, but there are many more:



  14. Re: concerned parent, there is the problem with the world today. Everything you believe came from a meeting put on by the police. It’s difficult to know what to say to a person who blindly accepts what this legal gang have to say. Do you not read any other articles, just this one? The police have so much vested interest in this topic, one could literally get a more unbiased opinion of whether to buy a Honda from a Toyota sales rep. At least the Toyota guy would have only a few hundred dollars on the line, instead of a multi-million or billion dollar budget at stake. Do you have any idea how many police would need to be laid off if we were all to stop the war on cannibis? How do you think the police unions would react to that? Status quo is the permanent marching order.

  15. This piece fails to consider the possibility that the causality arrow runs counter to what those quoted suggested. In other words, people smoke because they are depressed (as opposed to getting depressed because they smoke).

  16. Most high school students and university students drink copious amounts of booze as well, which is a known depressant. Has this been taken into account for this “study”?

    Also, what about pharmaceutical drugs? The side effects from these depending on the drug, can cause cancer, suicide, depression, death, internal bleeding, ulcers, addiction, and a long list of psychiatric issues, yet doctors freely give them out. You can die from Tylenol, Aspirin, etc.

    On top of this, we’ve wasted billions of tax payers dollars over the last 100 years on this drug war and have gotten any where on it. This money can be used for infrastructure, after school programs for youth, education, community programs, paying debt, etc.

    If you ask me, a mother, who was against pot for many years until several car accidents, I say this is bust. I had to take many different pain killers to try to get through the day. I ended up getting mood swings, depression, insane stomach pains, nausea, migraines from these prescription drugs. It wasn’t until a few years of popping pain pills like candy that I saw the light of marijuana. I haven’t needed a pain killer in years now because of it. It really helped get my life back on track in ways codeine never could.