Personality variables in cocaine- and marijuana-dependent patients

Khantzian (1985) hypothesized that the drug of choice of patients with substance-dependence disorders reflects an attempt at self-medication. Cocaine- and marijuana-dependent inpatients were compared using the MMPI to test this hypothesis. These two groups of patients did not differ on the standard validity and clinical scales of the MMPI, and their scores were basically similar to a group of alcohol-dependent inpatients and a group of psychiatric patients of similar age. There was no single MMPI code type that was characteristic of either group of substance-dependent patients. It appears that drug of choice had little effect on the MMPI scores of these two groups of substance-dependent patients. These results are not consistent with the theory of self-medication.