Millon Adolescent Substance-Abuse Proneness Scale: Identifying Clients in a Forensic Setting

Abstract

This archival study examined the effectiveness of the Millon Adolescent Clinical Inventory Substance-Abuse Proneness scale in identifying clinically diagnosed alcohol and drug abusers in a diverse sample of 339 adjudicated adolescents in a forensic assessment setting. There was a highly significant difference on base rate scale scores between groups diagnosed with a substance use disorder and no disorder (χ2 = 50.38, p < .0005), indicating some discriminate validity of the scale. There was a significant, but moderate, positive correlation between the clinical diagnosis and scores on the scale (rs = .384, p < .0005) with a small effect size (.148) indicating some concurrent validity of the scale. However, only 27.36% of the adolescents who were diagnosed with a substance abuse disorder and 26.09% diagnosed with a dependency disorder were identified with the recommended base rate cut-off score of 75. Using the same cut-off a higher percentage (46.05%) of clients diagnosed with both abuse and dependency were identified by the scale. African American youth were the least likely, and Caucasian youth the most likely to be correctly identified by the scale. These findings raise questions about the validity and clinical utility of this scale, especially with adolescents who may be motivated to minimize their substance use or are being assessed in a forensic setting.