The researchers also report that “estimates of the attributable risk suggest that the use of cannabis accounts for about 10 percent of cases of psychosis.”
The findings are based on 131 patients ages 15 to 65 years who needed inpatient care for a first psychotic episode during a 2-year period. The subjects were evaluated using the Structured Clinical Interview for DSM-IV Axis I Disorders, and clinical and demographic data were also collected.
The results showed a significant gradual reduction in the age at which psychosis began that correlated with an increased dependence on cannabis. Compared with nonusers, age at onset was reduced by 7, 8.5, and 12 years among users, abusers and dependents, respectively, the researchers report.
In further analysis, the effect of cannabis on age at onset “was not explained by the use of other drugs or by gender,” they also note. The finding was similar in the youngest patients, suggesting that this effect was not due to chance.
Imagine that. Hardcore use of a mild hallucinogen causes brain dysfunction! Now I understand Daily Kos diarists and ANSWER in a whole new light.