Long-term users of marijuana gradually become worse at learning and remembering things, a new study suggests.
“It definitely fogs your brain,” says Lambros Messinis, who led the study at the University Hospital of Patras in Greece.
Messinis and colleagues tested the mental abilities of 20 long-term users who had taken marijuana heavily – smoking at least four joints a week – for an average of 15 years. Their brains were rustier than those of 20 short-term users – who had averaged seven years of use – and 24 controls who had used the drug sporadically or not at all.
Long-term users performed worse in tests to measure memory, learning ability and the capacity to recall information. Asked to recall lists of 15 words that they had seen earlier, for example, the long-term users averaged seven, compared with nine recalled by short-term users and 12 by controls.
“Long-term users found it very difficult to learn through new information given verbally,” says Messinis. “It’s not to do with lack of attention but more the encoding process of memory.” Separate tests to probe attention span found that long-term users were able to pick up information immediately, without trouble.
Maybe they just didn't care about the results of the test??? Or maybe the control subjects really really did!
New Scientist Long-term marijuana use may fog the brain - Breaking News