Determining a Diagnostic Cut-off on the Severity of Dependence Scale (SDS) for Cocaine Dependence

Aim: The study aimed to assess the efficacy of the Severity of Dependence Scale (SDS) as a diagnostic measure of cocaine dependence and determine the cut-off score that best discriminates between the presence and absence of a DSM-IV diagnosis of cocaine dependence.

Design: Cross-sectional survey.

Setting: Sydney, Australia.

Participants: One hundred and forty-two cocaine users.

Measurements: The diagnostic performance of the SDS was measured via ROC analysis against DSM-IV diagnoses of cocaine dependence, as measured by the Composite International Diagnostic Interview (CIDI).

Findings: ROC analysis revealed the SDS to be a test of high diagnostic utility for the measurement of cocaine dependence. The cut-off point on the SDS at which there is optimal discrimination between the presence and absence of a DSM-IV diagnosis of cocaine dependence was found to be 3 (i.e. a score of 3 or more).

Conclusions: The study statistically validated the utility of the SDS as a diagnostic measure of cocaine dependence and has determined an appropriate cut-off point. The SDS is recommended as a brief screening instrument for cocaine dependence that can be used in addition to more comprehensive measures, such as the CIDI.