Greater Marijuana Use Linked to More Severe Schizophrenia
New research reveals that schizophrenia patients with a history of cannabis use have longer hospital stays and a higher rate of hospital readmission. 

Canadian Kids Smoke The Most Marijuana In The Western World, According To UNICEF Survey:
A new study conducted by UNICEF on child well-being found that Canadian kids smoke more marijuana than kids from any other developed country.

Effects of cannabis use on event related potentials in subjects at ultra high risk for psychosis and healthy controls.
Cannabis use has consistently been associated with psychotic symptoms as well as cognitive impairments. 

Does Change in Cannabis Use in Established Psychosis Affect Clinical Outcome? 
Background: Cannabis use has been identified as a potent predictor of the earlier onset of psychosis, but meta-analysis has not indicated that it has a clear effect in established psychosis.

Cannabis, psychosis and the thalamus: A theoretical review
The role of cannabis in the etiology of schizophrenia has been documented as possibly the strongest environmental risk factor.

Psychosis-inducing effects of cannabis are related to both childhood abuse and COMT genotypes