“Casual marijuana use damages the brain” conclude researchers at Northwestern University in new study. Doctors find the degree the brain changed is directly related to the amount of marijuana being used.
Casual marijuana use linked to brain changes
Karen Weintraub, Special for USA TODAY
6:46 p.m. EDT April 15, 2014
Using marijuana a few times a week is enough to physically alter critical brain structures, according to a new study published Tuesday in The Journal of Neuroscience.
“Just casual use appears to create changes in the brain in areas you don’t want to change,” said Hans Breiter, a psychiatrist and mathematician at the Northwestern University Feinberg School of Medicine in Chicago, who led the new study.
There is actually very little research on the potential benefits and downsides of casual marijuana smoking — fewer than four times a week on average.
In his study, done in collaboration with researchers at Harvard University, scientists looked at the brains of 20 relatively light marijuana users and 20 people who did not use it at all. All 40 were college students in the Boston area.
The study found volume, shape and density changes in two crucial brain areas — the nucleus accumbens and the amygdala — involved with emotion and motivation and some types of mental illness. “This is a part of the brain you do not want to mess around with,” Breiter said.
The more marijuana the students smoked, the more their brains differed from the non-users, the study found.
The brain continues to develop well into the 20s, and even into the 30s, said Breiter, who is concerned about the long-term impacts of marijuana use on the developing brain.
Staci Gruber, an associate professor of psychiatry at Harvard Medical School, who was not involved in the research, said Breiter’s findings are consistent with her own, although she has focused on somewhat heavier users.