Marijuana linked to brain damage

Adolescents who regularly smoke marijuana risk damaging a key brain pathway associated with language development, and some predisposed to schizophrenia may contract the illness early, researchers said Wednesday, also at the meeting of the Radiological Society of North America.

Brain scans revealed microscopic abnormalities in a region of the brain that governs higher aspects of language and listening functions in adolescents who are heavy marijuana smokers.

Similar damage to the bundle of fibers, called the arcuate fasciculus, that connect Broca’s area in the left frontal lobe and Wernicke’s area in the left temporal lobe was found in the brains of marijuana smokers and schizophrenics studied.

The researchers, from Albert Einstein College of Medicine in New York, scanned the brains of 114 subjects, 26 of whom were selected because they were diagnosed schizophrenics. Of the schizophrenic group, 15 smoked marijuana. Another 15 subjects were nonschizophrenic adolescent male marijuana smokers who were matched against nonsmokers. It was those smokers whose scans showed abnormalities in the language and listening pathway.

The language pathway continues to develop during adolescence and is susceptible to neurotoxins, the researchers said.