Pubdate: Tue, 24 Mar 2015
Source: Washington Post (DC)
Copyright: 2015 The Washington Post Company
Contact:  http://www.washingtonpost.com/
Details: http://www.mapinc.org/media/491
Author: Linda Searing

Quick Study

Pot and the Brain

DOES MARIJUANA USE IN TEEN YEARS CAUSE MEMORY PROBLEMS IN ADULTHOOD?

THE QUESTION When a person smokes marijuana, the chemical THC goes 
quickly to the brain, producing a mood alteration. How might this 
affect memory?

THIS STUDY analyzed data on 54 people in their mid-20s. Some had 
smoked marijuana almost daily for about three years when they were 
teens but had not smoked it for about two years. The other 
participants had no history of heavy drug use. All were given brain 
scans and a battery of standardized memory tests to assess their 
ability to recall information. Among those who had smoked marijuana 
almost daily, the scans showed an abnormally shaped hippocampus, the 
part of the brain that is key to longterm memory. The longer they had 
smoked marijuana, the more abnormal the brain shape. On the memory 
tests, people who had once been heavy marijuana smokers scored about 
18 percent worse than those who had never smoked marijuana regularly.

WHO MAY BE AFFECTED? Teenagers who smoke marijuana now and adults who 
smoked marijuana heavily in their teen years. The National Institute 
on Drug Abuse notes that marijuana affects brain development, which 
can be problematic for teenagers because their brains are still developing.

CAVEATS The study included a small number of participants. Data on 
marijuana use came from the participants' responses to interview 
questions. The study did not determine whether the observed effects 
were permanent or would change over time. It is possible that the 
change in brain shape and memory issues occurred before the marijuana use.

FIND THIS STUDY March 11 online issue of Hippocampus, viewable at 
onlinelibrary.wiley.com/doi/10.1002/hipo.22427/ abstract.

LEARN MORE ABOUT marijuana and memory at www. drugabuse.gov (search 
for "marijuana"). Learn about the brain at www. strokeassociation.org 
(search for "brain tour").

The research described in Quick Study comes from credible, 
peerreviewed journals. Nonetheless, conclusive evidence about a 
treatment's effectiveness is rarely found in a single study. Anyone 
considering changing or beginning treatment of any kind should 
consult with a physician.
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MAP posted-by: Jay Bergstrom