Zur Zeit wandert ja – mal wieder – durch die Presse, dass Cannabis das Psychose-Risiko stark erhöhe. Ein guter Artikel dazu findet sich bei BadScience.

[…] It was also interesting to see how the risk was numerically reported. The most dramatic figure is always the relative risk increase, or rather: cannabis doubles the risk of psychosis, cannabis increases the risk by 40%. Because schizophrenia is comparatively rare, translated this into real numbers this works out – if the figures in the paper are correct, and causality is accepted – that about 800 yearly cases of schizophrenia are attributable to cannabis. This is not belittling the risk, merely expressing it clearly.

But whats really important, of course, is what you do with this data. Firstly, you can mispresent it, and scare people. Obviously it feels great to be so self-righteous, but people will stop taking you seriously. After all, youre talking to a population of young people who have worked out that you routinely exaggerate the dangers of drugs, not least of all with the ridiculous modern cannabis is 25 times stronger fabrication so beloved by the media and politicians.

And craziest of all is the fantasy that reclassifying cannabis will stop six million people smoking it, and so eradicate those 800 extra cases of psychosis. If anything, for all drugs, increased prohibition may create market conditions where more concentrated and dangerous forms are more commercially viable. Were talking about communities, and markets, with people in them, after all: not molecules and neuroreceptors.

Tja, immer wieder das gleiche alte Spiel mit Studien…