Their brains were rustier than those of 20 short-term users who had averaged seven years of use and 24 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, the long-term users averaged seven, compared with nine recalled by short-term users and 12 by controls.
--Edited IANS