Validity of the MCMI Drug Abuse Scale with drug abusing and psychiatric samples

The validity of the Drug Abuse Scale (T) from the Millon Clinical Multiaxial Inventory (MCMI) was studied by administering the MCMI to 75 White male veterans who were seeking treatment for opioid or cocaine dependence and 60 White male veterans without diagnoses of drug dependence who were receiving psychiatric care. Only (39.4%) of the drug-abusing sample was classified correctly by obtaining base rate (BR) scores above the clinical relevant cut-off of 74, whereas, only 12% of the psychiatric sample was misclassified by having obtained a BR above 74. The results suggest that the MCMI T Scale is limited in its ability to identify drug users, but is also unlikely to misclassify psychiatric patients as drug abusers when they are not. The authors urge caution in using the Drug Abuse Scale for the purpose of identifying drug abusers.