Smoking Marijuana Just Once Per Week May Cause Brain Damage


NEW YORK (MainStreet) — The old egg in a frying pan thing is back. This is your brain. This is your brain on drugs. A new study, released today in the Journal of Neuroscience, indicate that for young, recreational marijuana users, smoking as little as one joint a week can cause structural abnormalities in the brain.

Also See: Marijuana Can Treat Brain Injuries

Dr. Hans Breiter of Massachusetts General Hospital and Harvard Medical School led a team of researchers who collected high-resolution MRI scans on casual marijuana users between the ages of 18 and 25 years. Although the researchers note that animal studies have shown structural changes in brain regions related to cannabis ingestion, less is known about how recreational marijuana use affects the same gray matter density in humans.

Also See: Does Marijuana Induce Psychosis

"Although most previous studies have investigated the effect of cannabis use in heavy, dependent users, the present study posed the question of whether even recreational use may be associated with brain abnormalities," the report says. "The present study demonstrates that, even in young, nondependent marijuana users, morphometric abnormalities relative to nonusers are observable, many of which are exposure dependent."

The brain regions impacted involve human emotion and motivation. The study concluded that the more cannabis consumed, the greater the abnormalities.

"The results of this study indicate that in young, recreational marijuana users, structural abnormalities in gray matter density, volume, and shape of the nucleus accumbens and amygdala can be observed," the study concluded. "Pending confirmation in other cohorts of marijuana users, the present findings suggest that further study of marijuana effects are needed to help inform discussion about the legalization of marijuana. These results extend prior studies showing that drugs of abuse that are known to elevate release are associated with structural abnormalities in the brain and related disruptions in behavior."

According to 2008 statistics from the U.S. Department of Health and Human Services, marijuana is consumed by 15.2 million people per month. Two states have legalized marijuana for adult recreational use, and 20 states have passed laws allowing its use for medicinal purposes.

--Written by Hal M. Bundrick for MainStreet

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