The effect of cannabis on the brain: can it cause brain anomalies that lead to increased risk for schizophrenia?
OBJECTIVE
This review explores what is known about the association of cannabis with schizophrenia, its effects on the brain, and whether the brain changes known to be present in schizophrenia could be caused by cannabis and thus lead to a psychosis.


RESULTS
The heavy use of cannabis is known to be associated with some adverse consequences, such as the occurrence of acute psychotic episodes and the development of chronic schizophrenia in some people even after its use has terminated. Recent studies have produced controversy about whether cannabis in heavy use can cause irreversible brain damage, particularly to adolescents, and thus whether a chronic psychosis could be a result of brain changes caused by cannabis.


CONCLUSIONS
From the evidence that exists, it appears that the above view is unlikely and that cannabis may even have benign effects on brain structure, not producing deleterious damage. Its neurochemical interactions with the dopaminergic pathway, however, may, particularly in genetically vulnerable individuals, have adverse consequences.
DeLisi
Lynn E
LE
New York University, New York, NY 10016, USA. delisi76@aol.com
D001921:Brain / Q000187:drug effects* / Q000503:physiopathology*; D002188:Cannabis / Q000009:adverse effects*; D006801:Humans; D008279:Magnetic Resonance Imaging; D002189:Marijuana Abuse / Q000453:epidemiology; D015995:Prevalence; D011605:Psychoses, Substance-Induced / Q000209:etiology; D012307:Risk Factors; D012559:Schizophrenia / Q000139:chemically induced* / Q000453:epidemiology / Q000503:physiopathology*