Teenage stoners beware: Smoking pot now may cause you to forget things as adults.
Young adults who were heavy pot smokers as teens performed about 18 percent worse on long-term memory tests than those who never “abused cannabis,” Northwestern University researchers have found.
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And when those teens enter adulthood, poor long-term memory could affect their daily lives, said Matthew J. Smith, an assistant professor of psychiatry and behavioral sciences at the Feinberg School of Medicine and one of the researchers.
“If you just think about being able to engage in work activities where you should be remembering events at work or information at work, that can be an issue,” he said.
The scientists also found the hippocampus — a part of the brain linked to long-term memory — of the former teen stoners was abnormally shaped.
Smith and others at Northwestern studied people who had started using marijuana daily when they were 16 or 17 years old. At the time of the study, they had not used marijuana for about two years.
Researchers told their subjects stories and then 30 minutes later, the former pot users were asked to remember as much as possible.
“It’s what you can remember from that conversation 30 minutes later,” Smith said. “It’s pretty applicable for everyday life.”
The scientists also used high-tech tools to map their subjects’ brains and found the changes in the hippocampus were “more severe the longer they had been using cannabis,” Smith said.
Northwestern officials billed the study, published Thursday, as among the first to link the misshaped hippocampus and the resulting memory issues to heavy marijuana use.
In 2012, a landmark study determined that heavy use of marijuana by children under 18 harmed their IQ and memory.