Good reporting

A few days back I yammered about how the quality of journalistic reporting has gone to hell in a handcart. But the fact that I'm criticize deficiencies doesn't imply I won't compliment a job well done. And just such a piece is this article on marijuana use. Note the headline:

Marijuana Use Can Up Psychosis Risk

Very eye catching and attention grabbing. Of course, that's what headlines are for. Just as the cover of a comic book is designed to get you to pick it up and buy it (and often have only a passing relationship to the content within) so too do headlines exist to get you to read on.

As you might infer, the article is about rates of non-affective psychosis amongst both users and abstainers from marijuana. But here's why I'm giving the author a thumbs up. As always, he got the caveats and limitations from the scientists doing the work. But NOT as always, he included them. Here they are:

But the association between psychosis and marijuana use is not simple, the researchers noted. They found that people who'd experienced hallucinations earlier in life were also more likely to have used marijuana longer and to use it more frequently.

"This demonstrates the complexity of the relationship: those individuals who were vulnerable to psychosis [i.e., those who had isolated psychotic symptoms] were more likely to commence cannabis use, which could then subsequently contribute to an increased risk of conversion to a non-affective psychotic disorder," wrote the study authors.

Further research is needed to learn more about the mechanisms underlying the association between psychosis and marijuana use, they concluded.

Believe it or not, this constituted a third of the whole article. Many journalists would have given it a miss for that reason alone. But it's good the author didn't.

The whole point of the article is that users of marijuana were twice as likely to develop non-affective psychoses. Sounds bad. However what the scientists point out is that those people who had hallucinated while younger were more likely to start using marijuana. It's the old chicken and egg problem. Did the people exhibit increased psychoses BECAUSE they used marijuana or are people who are inherently more susceptible to psychoses more likely to start using marijuana (and then exhibit the symptoms)?

This type of question is so important. Logicians know that just because rich people drive Ferraris that does not imply that driving a Ferrari will make you rich. In an ideal world it shouldn't be necessary to state such caveats because everyone would realize they're there. Sadly, our world isn't ideal and these sorts of goofy "causation by association" conclusions are all too common in the media. So once again, yay for this guy giving complete reporting its due.

- And that's today's word from the bird