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Here’s How Smoking Too Much Pot As A Teen Can Mess Up Your Adult Brain

A new study says daily stoners can develop long-term ... wait, what were we talking about?

Marijuana is now legal in four states and the residents haven't all devolved into deranged killer cannibals, as the public may have feared back in the "Reefer Madness" era. But (non-medical) pot use is still illegal for minors in those states, due to its apparent different effects on the developing brain.

Researchers at Northwestern University released a study today in the journal Hippocampus linking heavy pot use in the adolescent years to impaired memory in the adult years. Even after retiring their bongs for 24 months, former daily smokers averaged 18% lower recollection.

The researchers' previous research had linked marijuana to short-term memory loss...

...but now experts say they've used brain-mapping technology to detect "detailed and sometimes subtle changes" to the hippocampus, which is responsible for the "ability to remember autobiographical or life events." (Like, y'know, the 365+ times per year you were smoking up.)

The Northwestern study involved nearly 100 subjects who'd started smoking regularly at 16 or 17, continued for approximately three years and then had abstained for two years.

"Both our recent studies link the chronic use of marijuana during adolescence to these differences in the shape of brain regions that are critical to memory and that appear to last for at least a few years after people stop using it," said Dr. Matthew Smith, assistant professor of psychiatry and behavioral sciences, who led the study.

As Dr. Frances Jensen, neuroscientist and author of "The Teenage Brain," told MTV News back in January:

“You may think your IQ is set. Well, guess what? In your teen years, one-third [of people] stay the same, one-third go down and one-third go up. You can go up! We don’t know why that happens, but we do know if you’re smoking pot daily, your IQ drops. … Binge-drinking can cause more brain damage [for you] than it would for your alcoholic uncle.”