Does Pot Make you Stupid?

In the short term, yes, but the best study yet finds no long term effect on cognitive abilities. The researchers say that previous studies finding an effect on verbal ability failed to control for the social profile of pot smokers, who are largely lower-class men. Lower-class men perform worse than women and the well-educated on tests of verbal ability, and once this correction is applied, the alleged long-term effect of marijuana use disappears.