Assessment of cocaine and other drug dependence in the general population: "gated" versus "ungated" approaches.

BACKGROUND There is a need for large-scale epidemiological surveys to be (a) faithful to diagnostic specifications and (b) constrain time and participant burden associated with each section of a possibly lengthy interview. OBJECTIVE To examine whether one "gating" approach devised for recent large-scale international psychiatric surveys results in a reduced number of identified cases of drug dependence and/or biases in estimated associations with background characteristics. DESIGN AND SETTING Data from a recently released cross-sectional, nationally representative household survey, the United States National Epidemiologic Survey on Alcohol and Related Conditions (NESARC) were analysed. PARTICIPANTS Forty-three thousand ninety-three English speaking adults aged 18 years and over. MAIN OUTCOME MEASURES Dependence upon cocaine and other illegal drug dependence, defined in two ways: "ungated" and "gated". "Ungated" dependence included all persons meeting criteria for DSM-IV dependence, without regard for DSM-IV drug abuse clinical features. "Gated" dependence required at least one feature of DSM-IV drug abuse. RESULTS There was no statistically robust decrement in the estimated prevalence of cocaine or other drug dependence using a "gated" assessment. Patterns of association of cocaine dependence with background characteristics were not appreciably different when the gated and ungated approaches were applied. CONCLUSIONS In panoramic mental health surveys, the inefficiency of an ungated approach must be balanced against the anticipated number of cases of dependence without associated social role impairments or harm. In this study, the reduction in the number of identified cocaine dependence cases appeared to be so small that even in a sample of over 40,000 participants, attenuation in population prevalence would prove difficult to detect.