Robert L Tanguay completed his BSc from the University of Lethbridge, attended Medical School at University of Calgary and did his Residency in Psychiatry. He completed his Fellowship in Addiction Medicine under the guidance of Nady el-Guebaly. He is also a Pain Medicine Fellow in the Department of Anesthesia at University of Calgary. He is actively involved in education, teaching medical students and psychiatry residents at the University of Calgary.


We reviewed the literature that proposes the mechanisms of cannabis induced psychotic disorders and hence, increases the risk of early onset of schizophrenia. There have been recent studies showing psychosis as secondary to the THC levels in marijuana, and several studies were found showing CBD may be protective and actually have antipsychotic properties equal in efficacy to atypical antipsychotics such as amisulpride. The percentage of THC is much higher today than in the past and certain formulations have been able to even further concentrate THC such as shatter, wax, honey oil, etcetera. Complicating this is that CBD is almost nonexistent in illicit and legal marijuana around the world. Due to Mendelian genetics, as THC concentration is increased, CBD concentration seems to be inversely reduced. This eliminates the protective factors of CBD while increasing the risk of psychosis. THC and CBD seem to have opposite physiologic effects on endogenous anandamide levels and cannabinoid receptor binding, the mechanism likely leading to CBD’s antipsychotic effect.