Association between cannabis use and psychosis
Previous studies have shown that cannabis use is more frequent among patients with psychotic disorders than in the general population.
However, the issue of reversed causality, ie, that experiencing psychotic symptoms or having an emerging psychotic disorder may increase the risk for cannabis use, and the fact that cannabis intoxication may lead to psychotic-like symptoms, must be carefully addressed.
Genetics and environment
In this study, cannabis abuse disorder was found to have a heritability of almost 90%, while psychosis had some minor heredity. The correlation between the two disorders was high.
A model that says cannabis gives rise to psychosis fits better with the data than alternative explanations. Such a relationship has both genetic and environmental explanations.
Read the full article in Schizophrenia Bulletin here.