According to Australian researchers, people who develop psychosis and smoke marijuana brought the illness on almost three years earlier than those sufferers who did not smoke pot.
Dr. Matthew Large, a senior staff psychiatrist at Prince of Wales Hospital in Sydney, who wrote the article, gathered his data from 83 peer-reviewed, related studies that included almost 8,200 people who smoked pot and almost 14,400 who did not use drugs.
The study also suggests some psychosis patients developed the disease because of their use of pot. Large said one in twenty pot smokers, who start in their teens, developed psychosis; as compared to the rate of one in fifty in adults. Some members of the psychiatric community are not convinced; psychiatric nurse practitioner, Michael Rice of the University of Nebraska Medical Center in Omaha, proposes the hypothesis that schizophrenia is caused by a brain inflammation and sufferers turn to pot for its anti-inflammatory properties. Other researchers point out the complexities of this problem make it difficult to believe it has one cause, instead they think multiple risk factors lead to its onset.
The study, published online February 7th, will be printed in the June issue of the Archives of General Psychiatry.

A talented demonstration of poor science, a meticulously constructed analysis of overly selective study review, from a pool of questionable science to start with, as noted by a feb 2010 journal of addiction study.
Prohibition will tout this as gospel and like the february study states as the media will sensationalize and misinterpret the results of studies pertaining to such a sensitive topic.