Bummer, Man

Long-term heavy use of marijuana may cause two important brain structures to shrink, Australian researchers said on Monday. I'm sorry, can you repeat that?

Brain scans showed the hippocampus and amygdala were smaller in men who were heavy marijuana users compared to nonusers, the researchers said. The men had smoked "at least five marijuana cigarettes" daily for on average 20 years. Damn, calling them marijuana cigarettes makes it sound totally uncool.

The hippocampus regulates memory and emotion, while the amygdala plays a critical role in fear and aggression. The study also found the heavy cannabis users earned lower scores than the nonusers in a verbal learning task -- trying to recall a list of 15 words. Yeah, well, what list of 15 words? I bet if pizza, interweb, and Will Ferrell were chosen they'd remember.

Among the 15 heavy marijuana users in the study, the hippocampus volume was 12% less and the amygdala volume was 7% less than in 16 men who were not marijuana users. The researchers acknowledged that the study did not prove it was the marijuana and not some other factor that triggered these brain differences but the findings certainly suggested marijuana was the cause. Marijuana users were more likely to exhibit mild signs of psychotic disorders, but not enough to be formally diagnosed with any such disorder, the researchers added. While about half of the marijuana users reported experiencing some form of paranoia and social withdrawal, only one of the nonusers reported such symptoms. The heavy marijuana users, average age 40, said they had used other illicit drugs less than 10 times.

Supporters of legal sales and regulation of marijuana took issue with the findings, particularly because they were based on men who were such heavy, long-term users.

"These were people who were essentially stoned all day every day for 20 years," said a Marijuana Policy Project spokesman. "This study says nothing about moderate or occasional users, who are the vast majority -- and the (study) even acknowledges this. The documented damage caused by comparably heavy use of alcohol or tobacco is just off-the-charts more serious, and you don't need high-tech scans to find it."

Researchers have begun new research on the effects of both short-term and long-term and moderate and heavy use of marijuana. Who ever wrote that last sentence must be high.