Marijuana and psychosis

There is a German study that finds evidence that marijuana use precedes psychosis.

If you haven't been following the science pretty closely, this may come as news to you so a little background. It has long been known that there is a higher incidence of psychosis among marijuana users than among the general population. You probably haven't heard much about it for two reasons.


In the first place, there has been very little media coverage which is odd. Marijuana use is very common in high schools, and has been for five decades now, so you would think that if there was a risk that something a lot of high school kids did might be making them crazy that the usual suspects would be screaming blue murder. But they aren't.

Correlation does not imply causation you say? True enough but there are other substances that have been taken off the market on the basis of about the same correlation between their and cancer as exists with marijuana and psychosis.

The second reason that you may not have have heard about this is that many in the scientific community have done everything they can to try and explain away this correlation rather than looking for possible causal links. A few years ago The Lancet devoted a major article to minimizing fears on this front. Yes, that is the same The Lancet that published the bogus study linking childhood vaccination to autism.

By the way, you can tell scientists are playing fast and loose when they respond to some new findings with a "literature review". It takes time for research to get published so the existing literature will always conflict with new findings. That doesn't mean the new findings are right but the way to check new findings is to try and duplicate them with further research. Responding, as The Lancet did to previous research in this area, to new findings with a literature review is the scientific equivalent of putting your fingers in your ears and singing "la la la" as loud as you can.

None of which means that the new study is solid goods. But seriously, you smoke a joint and it affects your brain; it makes it malfunction in odd and disturbing ways. Why don't people worry about that much more than they do?

As long as I'm ranting, I might add this: the most common way of explaining away the correlation between marijuana use and psychosis was to say that the people with psychosis were self-medicating. Okay, supposing that were true, is it even remotely a good idea for someone with psychosis to be self medicating with illegal drugs? Of course not and that tells you that they never meant it in the first place. If you really believed that thousands of victims of psychosis were doing something that risky you'd be screaming at anyone who would listen that we have to do something about this. But if you were just plugging your ears and singing because you'd rather not know?