A preliminary evaluation of the potential usefulness of the diagnoses of polysubstance dependence.

OBJECTIVE

The concept of polysubstance dependence (PD) has been defined several ways over the years. However, few clinicians and researchers appear to use this label in a manner consistent with any of the major diagnostic manuals. This article evaluates the prevalence and characteristics associated with PD in participants in a large collaborative study.

METHOD

In DSM-IV, PD characterizes people who do not meet criteria for dependence on any one substance but, when all drugs of abuse are considered have experienced three or more of the seven dependence items across the substances. In this study, structured face-to-face interviews were administered to 8,834 men and women as part of the Collaborative Study on the Genetics of Alcoholism. The 198 subjects (2.2%) with a slightly expanded concept of the DSM-IV disorder were compared with men and women with dependence on alcohol, marijuana or stimulants, subjects with substance abuse and those with no substance use disorder.

RESULTS

In this dataset, compared with subjects with a specific substance dependence, those with PD were slightly more educated and less likely to be divorced or separated, and they had fewer substance-related problems. At the same time, those with PD had more substance problems than did subjects who only met criteria for abuse. These basic conclusions were unchanged among the subset of 59 subjects who met the more restricted, classical DSM-IV PD criteria.

CONCLUSIONS

The data indicate that, while relatively rare, subjects with PD might differ in potentially important ways from those with dependence or abuse on specific drugs. A large prospective study of a group with carefully defined PD is needed.