Research Assistant in Psychological Medicine at the Christchurch School of Medicine & Health Sciences at the University of Otago, New Zealand
Not Clearly Pro or Con to the question "Should Marijuana Be a Medical Option?"
"Regression models adjusting for observed and non-observed confounding suggested that daily users of cannabis had rates of psychotic symptoms that were between 1.6 and 1.8 times higher (P<0.001) than non-users of cannabis...
The results of the present study add to a growing body of evidence suggesting that regular cannabis use may increase risks of psychosis.
The present study suggests that:
A. the association between cannabis use and psychotic symptoms is unlikely to be due to confounding factors; and
B. the direction of causality is from cannabis use to psychotic symptoms."
"Tests of Causal Likages Between Cannabis Use and Psychotic Symptoms," Addiction, 2005