Swedish study: heavy teenage marijuana use cuts life expectancy – pretty dramatically

Not sure what their definition of "heavy" is, but increases chance of death prior to age 60 by 40%. A pretty interesting 42 year study.

Swedish researchers analyzed the records of more than 45,000 men beginning in 1969 and 1970. The scientists from the Karolinska Institutet in Stockholm reported that 4,000 died during the 42-year follow-up period, and men who'd used marijuana heavily at ages 18 and 19 were 40 percent more likely to die by age 60 compared to guys who hadn't used the drug.

The authors of the new study, published in the American Journal of Psychiatry, said the findings contradict previous research involving the same group of men.

But this study was longer and participants might have reached an age where the long-term effects of cannabis were taking a toll on health, said addiction expert Scott Krakower, an assistant unit chief of psychiatry at Zucker Hillside Hospital, in New Hyde Park, NY.

"Cannabis users have poorer health in general. You'd expect there to be increased mortality risk," Krakower told CBS News. He pointed to another long-term study linking early heavy marijuana use with lung cancer, and a second study that associates the drug with increased heart problems.

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Hill, an assistant professor of psychiatry at McLean Hospital and Harvard Medical School, said most people who use marijuana don't use it at heavy levels. "Nine percent of adults use it at that level and develop an addiction."

He said the study is limited because it didn't provide specifics about heavy use and continued use.

Using marijuana earlier in life is linked to poorer psychological health, he said, and that can contribute to more health problems down the road.