Brain scans link pot, schizophrenia

CHICAGO, Dec. 1 (UPI) -- Brain scans show adolescents using marijuana have brain construction deficits similar to schizophrenia.

In fact, researchers using a technique called diffusion tensor imaging report that adolescents who are genetically at risk for schizophrenia may increase that risk by heavy use of marijuana.

Manzar Ashtari, a scientist at Zucker Hillside Hospital, Glen Oaks, N.Y., showed in four small studies "that marijuana affects areas of the brain that are still developing during adolescence and these are the same areas that are affected by schizophrenia."

Non-drug-using, healthy adolescents have significant developmental activity in the arcuate fasciculus -- an area of the brain still developing during late childhood.

Damage in this area of the brain was evident in scans from 15 otherwise healthy marijuana smokers and 15 schizophrenics who smoked marijuana. This brain region controls speech development, language interpretation and higher-order functions.

The studies show heavy marijuana use could trigger schizophrenia in adolescents genetically at risk for the mental disorder, but Ashtari cautioned that the studies are limited by their small size.