Early marijuana use a bigger problem
Researchers at Harvard-affiliated McLean Hospital have shown that those who start using marijuana at a young age are more impaired on tests of cognitive function than those who start smoking at a later age. The study results will be presented on Monday (Nov. 15) at the annual meeting of the Society for Neuroscience in San Diego. Staci A. Gruber reported that subjects who started using marijuana before age 16 made twice as many mistakes on tests of executive function, which includes planning, flexibility, abstract thinking, and inhibiting inappropriate responses, as those who began smoking after age 16. “They performed significantly worse,” said Gruber, director of the Cognitive and Clinical Neuroimaging Core at McLean and assistant professor of psychology at Harvard Medical School (HMS). The early-onset users also smoked three times as much marijuana per week and twice as often compared with the later-onset users, she noted. “Our data suggest that the earlier you begin...