USA Today (4/16, Weintraub) reports that according to a study published April 16 in the Journal of Neuroscience, “using marijuana a few times a week is enough to physically alter critical brain structures.”
The AP (4/16, Ritter) reports that the study involved 20 young adult marijuana users who “said they smoked marijuana an average of about four days a week, for an average total of about 11 joints.” Using magnetic resonance imaging, investigators “scanned their brains and compared the results to those of 20 non-users who were matched for age, sex and other traits.”
According to the Boston Globe (4/15, Lazar), these young adults displayed “abnormalities in two key areas of their brain related to emotion, motivation and decision making, and the degree of changes appear to be directly related to the number of joints smoked per week.” Those two areas are the nucleus accumbens and the amygdala. Researchers “did not study whether the changes were linked to corresponding declines in brain function, but say the signs suggest young people might be especially vulnerable because their brains are still developing.”
— “Casual marijuana use linked to brain changes,” Karen Weintraub, USA Today, April 15, 2014.