Few will be surprised that teens can be struck dumb by heavy pot smoking. What's interesting is the question that new research raises: Can kids under 16 get baked every now and then without limiting their long-term brain power?
Sixteen-year-olds who regularly enjoy marijuana show somewhat diminished grades, according to a new analysis of data on 2,235 British children born in 1991 and 1992. What the study considers moderate users -- teens who have smoked cannabis fewer than 50 times -- showed no similar losses on exams.
The children are members of an ongoing study at the University of Bristol that began with their mothers' pregnancies. They were given IQ tests when they were eight years old and again at 15, when they were also asked to complete surveys on cannabis use.
The new work, which is supported by the U.K. Medical Research Council, suggests that pot smoking may be a symptom of a larger problem. “Cigarette use, alcohol use and other recreational drug use, as well as cannabis use,” the authors write, “are all associated with IQ and educational decline.” Lifestyles that encourage pot smoking may be a hidden force behind the drop, “rather than a specific effect of cannabis consumption,” they said.