The three groups were compared on 28 personality measures using one way analyses of variance. There were no differences between the groups on a large number of measures including many for which differences had been previously reported. Students differed from one or both of the other groups on 13 items, while hostel residents differed from those in drug treatment on only 3 items. Drug use was best predicted by the MAC scale of the MMPI, which, to an extent, measured being street wise among other traits. Drug users were characterized as shrewd, toughminded, anxious, experience-seeking, and well motivated for the future. Many of the previously reported psychological correlates of drug use may be artifacts of using inadequate or incomparable control groups such as students or general population norms. In previous research, being streetwise may have been confused with being antisocial. 4 tables and 31 references (Author abstract modified)