This article reviews published 16PF research on drug users. It also compares the 16PF scores of a new sample of nonusers with scores of matched groups of heavy, chronic users of cocaine, amphetamine, opiates, and barbiturates/sedative hypnotics, as well as combined groups of stimulant users, depressant users, and a combined group of users of all substances. No significant differences were found among drug user groups, but the profile of the nonuser group was distinctive. K-Means Cluster Analyses, as well as Cattell's Similarity and Pearson Product Moment Correlation Coefficients, were used to compare profiles of these new samples with the 19 groups described in an earlier meta-analysis of published 16PF studies. Data from the new samples did not cluster with data from other published research, although certain specific similarities appeared in more detailed correlational analyses. Methodological problems are discussed, and it is recommended that in future studies drug user groups be more carefully selected and defined, sample descriptions be more thorough and complete, complete profile information be routinely provided, and efforts be made to explore the utility of the Cattell CAQ in studies of drug users/misusers.