abacacus wrote:
ValentineWiggin wrote:
No. Usage historically skyrockets when a substance is decriminalized, and the causative relationship between cannabis and psychotic illness places it in a category unique from currently-legal drugs...which themselves are responsible for millions of dollars in health care.
Cannabis does not cause psychosis. What it *can* do is trigger it in people who are already mentally ill.
Actually, the largest study ever done on the subject involved 46,000 subjects, controlled for pre-existing mental illness, and found using marijuana 1-10 times put users in a group 1.5 times more likely to be diagnoses with schizophrenia later in life, and using more than that resulted in odds 2.3 times greater. This was a longitudinal study, following participants for 15 years.
Schiophrenia in users and non-usersOther studies even accounted for other types of substance abuse, and confirmed the original findings.
Use as a Risk FactorOther studies show a link between transient psychotic symptoms in
healthy individuals and potent cannabis use.
Psychosis in Healthy PeopleThe evidence that memory and intelligence are negatively affected in heavy users is rock-solid, but we'll assume "heavy" by definition represents a non-majority number of users.
Until people plan on getting tested for the genetic markers for schizophrenia prior to usage of cannabis (which, by the way, I believe are still only estimated to be responsible for 50% of all cases), whether the drug causes it or acts in conjunction with genes is pretty moot.
Until you can cite a scientific article demonstrating a direct causality between THC consumption and schizophrenia, I call malarkey.