Reliability, diagnostic efficiency, and validity of the Millon adolescent clinical inventory: examination of selected scales in psychiatrically hospitalized adolescents

This study examined the internal consistency, diagnostic efficiency, and validity of selected scales of the Millon adolescent clinical inventory (MACI; Millon et al., Manual for the Millon Adolescent Clinical Inventory, National Computer Systems, Minneapolis, MN, 1993). 241 psychiatrically hospitalized adolescents were administered the MACI and a battery of established self-report measures and a multidisciplinary team independently assigned DSM-IV psychiatric diagnoses at the time of discharge. The internal consistency of MACI scales ranged from 0.71 to 0.93. Conditional probabilities (sensitivity, specificity, positive predictive power, and negative predictive power) were calculated for selected disorders using independently generated clinical diagnoses as the standard. The diagnostic efficiencies for the selected scales were variable, with adequate performance for predicting classes of diagnoses but not for specific diagnoses. The MACI showed good criterion validity for most disorders, with participants with a clinical diagnosis having a significantly higher corresponding MACI scale score than participants not assigned that diagnosis. Concurrent validity, tested by correlating MACI scale scores with those of relevant, validated measures, was generally good. The MACI appears to be a psychometrically sound self-report instrument and appears valuable as a screening instrument for many problems found in adolescent psychiatric inpatients.