Factor-based prototypes of the Millon Adolescent Clinical Inventory in adolescents referred for residential treatment

Although well received by the clinical community, there have been few published reports on the use of the Millon Adolescent Clinical Inventory (MACI). There have been no published studies describing use of the MACI with a residential treatment population. In addition, there have been no published reports investigating the factor structure of the MACI. A principal components factor analysis was performed for all MACI scales and sex for 251 adolescents referred to a residential treatment facility. Five factors were found accounting for 77.4% of the variance. Factor-based prototypes were generated from these results: Factor 1 defines a prototype for Defiant Externalizers, Factor 2 for Intrapunitive Ambivalent Types, Factor 3 for Inadequate Avoidants, Factor 4 for Self-Deprecating Depressives, and Factor 5 for Reactive Abused Types. Prototype descriptions and clinical vignettes are included for each of the 5 factor-based prototypes. These results are consistent with our clinical experience with this population. Prototype analysis may offer a powerful way of enhancing the utility of the MACI in clinical settings.