http://www.healthtalk.ca/psychosis_12012004_7023.php
in any case this is new evidence that might suggest that marijuana isn't as harmless as some of you make it out to be.
there is some uncertainty about the meaning of the results. from http://www.healthypages.net/newsstory.asp?newsid=4725 we find this quote:On average, the study found that young people using cannabis have about a 6 percent increased risk of developing psychotic symptoms, compared with non-users. Among those vulnerable to the condition, the risk jumps to 23.8 percent.
...
"Cannabis use moderately increases the risk of psychotic symptoms in young people but has a much stronger effect in those with evidence of predisposition for psychosis," concluded the researchers.
for those of you inclined to read the study itself instead of the reuters summary of it, the british medical journal has helpfully posted the article as a pdf, available here. i'm too lazy to actually read it tho: http://bmj.bmjjournals.com/cgi/rapidpdf/bmj.38267.664086.63v1 .Although a link between marijuana use and psychosis is well established, the direction of the association is unclear. That is to say, while cannabis use may cause psychosis, it is also possible that people predisposed to psychosis are simply more likely to use cannabis -- a theory called the self-medication hypothesis.
in any case this is new evidence that might suggest that marijuana isn't as harmless as some of you make it out to be.