Dimensions of Multiple Drug Use and a Typology of Drug Users (original) (raw)

An accurate evaluation of the effectiveness of substance abuse treatment depends largely upon the construction of measures which will capture the complexity of multiple substance use patterns. Of 256 subjects assessed for a drug abuse treatment programme, 90% had used drugs from four or more of eight classes (Alcohol, Cannabis, Hallucinogens, Narcotics, Sedative Hypnotics, Solvents, Stimulants, Tranquillizers) during the past year. A principal components analysis of frequency data from the drug classes indicated four orthogonal factors, explaining 72% of the variance. Cluster analysis (Ward's method) grouped subjects into five clusters, provisionally labelled A (predominantly alcohol), ADR (combining high use of alcohol,‘depressant’ and ‘recreational'drugs), D (predominantly ‘depressant’ drugs), R (mainly ‘recreational’ drugs) and S (very high use of solvents). Four of the clusters (A, D. R. S) combined drugs similar to the principal component factors, with a fifth cluster (ADR) indicating high use of all drug classes except solvents. The clusters also differed in several important ways, including age, social class, social stability, age at onset of drug problem, number of drug classes used, and present severity of drug and alcohol problems.