Psychosis and Marijuana

Unsurprisingly, only a few news organizations are covering this story. To my surprise, CBS News covered it on July 26, 2007, and without a bunch of excuses:

(WebMD) Smoking cannabis, or marijuana, as a youth could boost the risk of developing a psychotic illness later in life by about 40 percent, according to a new analysis of published studies conducted by British researchers.

The more than 40 percent increase in risk applies to those who have ever used the drug, and the risk rises even more with frequent use, according to Stanley Zammit, M.D., Ph.D., clinical lecturer in psychiatric epidemiology at Cardiff University and the University of Bristol in the U.K., a study co-author.

"People who have ever used cannabis, on average, have about a 40% increased risk of developing psychotic illness later in life compared with people who have never used cannabis," he tells WebMD.

"People who used it on a weekly or daily basis had about a 100% increased risk, or twofold." Even so, he adds, "the risk is still relatively low."

...

Zammit and his colleagues pooled the results of 35 published studies on marijuana use and mental health effects, including psychotic effects such as schizophrenia (in which people may hear voices or hallucinate) or affective problems such as depression and anxiety. They analyzed the results of all the studies, a method known as a meta-analysis.

The increased risk of psychosis with marijuana use persists, Zammit's team found, independently of the transient intoxication effects of the drug and independently of what they call "confounding factors," such as existing mental health problems or other drug use. "We can't be sure it is causal," he says of the association. "[But] studies find an association rather consistently."

Still, he tells WebMD, "It's always possible people who use cannabis may be different [in some way] than those who don't."

The researchers also looked at the association between marijuana use and depression and anxiety but found that the evidence is "less strong than for psychosis but is still of concern."

...

In an editorial in the same issue, Lancet editors note that the publication ran an oft-quoted editorial in a 1995 issue stating that "the smoking of cannabis, even long term, is not harmful to health." Now, the editors note, research published in the interim, including the meta-analysis, has triggered a change in their thinking, with them now stating that cannabis use "could increase the risk of psychotic illness" and that more research is needed on any link with depression and anxiety.

Now, it is certainly possible that this correlation isn't that marijuana causes psychosis; perhaps people who are prone to psychosis are attracted to marijuana. As I mentioned some months back, a longitudinal study done some years ago established that the drug abuse/mental illness connection was causal, and that the drug abuse increase preceded the mental illness increase. I am not sure which drugs they were counting; probably not marijuana, since they were looking at hospital admissions for drug problems, and that wouldn't include marijuana.

I've had several relatives whose bipolar disorder problems seem to have been greatly aggravated by marijuana use--pushing one of them into complete, decades-long disability, and another one very close to it. I know my brother was certainly smoking marijuana in the several years before his schizophrenic breakdown; I was astounded to visit his apartment at one point with my parents, and they didn't even notice the joint sitting on the coffee table--and this was at a time when marijuana possession was still a relatively serious crime in California.

Yes, the increase in psychosis rate isn't huge. Most people that smoke marijuana aren't going to become psychotic. What if you are one of the small minority that does. Do you feel lucky?

UPDATE: If you want to see a form of religious frenzy, read the comments on that CBS News story. Even the few people who managed to make a valid point--that it isn't clear whether this association is coincidence, or what the direction of causality is which the scientists quoted also pointed out--managed to make their points in a way that really shows you the desperation:

This report is not science. It's major BS! It's propaganda written to serve a predetermined right wing political agenda. Since before the time of Christ mankind has smoked marijuana and hashish. Over those thousands of years there has been ample time for all the ill effects of marijuana and hashish to be amply discovered and displayed. But now, suddenly, somehow some new effect has been surfaced that has escaped notice for all those many centuries?

Except that before modern epidemiology got its start in the 19th century examination of water-borne diseases (The Ghost Map is a very readable account), figuring out subtle connections like these were very hard to do. Unless a particular substance caused a very high fatality or morbidity rate, or the effects were visible almost immediately, it was very easy to miss.

50 years old. Smoked daily for over 30 years. Pay my bills on time. Take 1 or 2 sick days a year, if that. Keep a clean house. Eat right. Exercise daily. Recycle. Made a conscious choice not to have children.

What about me is psychotic?

Except that the study didn't make the claim that every marijuana smoker would become psychotic--only increase the incidence of psychosis.

Oh, This is part of the reason the feds were raiding that medical ganja clinic in LA, instead of helping to secure our borders. OOOOOHHHHH!

Speaks for itself.

Reefer Madness. It's all about social control. 100 years ago people had more freedom than we do today. There is a concerted, obvious effort on the part of the ruling class to use scare tactics, whether terror or drugs (both are the reason for "wars" waged by the U.S.), to convince people that their lives must be monitored and regulated by Big Brother, lest we harm ourselves or are hit by the odd suicide bomber. The mainstream media is, of course, the propaganda arm of the ruling class. In Albert Speer's book, 'Inside The Third Reich', he noted that Hitler was merely the first tyrant to make full use of modern mass communication. Such mass communication is now, of course, much more highly sophisticated. Read Noam Chomsky's books on propaganda and the mass media.

Ditto.

Where are all these poeple that have developed psychoisis from marijuana?

It's been used by humans since before we kept records with not one documented case of psychosis.

Maybe it just makes some people spell badly.

There is yet to be one record of anyone ever overdosing solely on Cannibis.

Children under the age of 16 shouldn't smoke or drink anything anyways (developing brain cells)

Devils weed?

You mean God made the planet in seven days and realized later he created a plant that grows everywhere... was a mistake???

And where did the article make any reference to overdosing?

Does marijuana turn people into fanatics? Or do fanatics start smoking marijuana? Or is the addiction so severe that they go crazy at the prospect of not getting it? If someone discovered tomorrows that limes cause some horrible illness, I would give up my Minute Maid Limeade. I wouldn't turn this into a bizarre theory about how Sunkist Growers had bought off scientists to destroy their competition.