An examination of the factor structure of the Millon Adolescent Clinical Inventory in a sample of detained adolescent boys.

Prior empirical examinations of the factor structure of the Millon Adolescent Clinical Inventory (MACI; Millon, 1993, 2006) have produced mixed results and have not included confirmatory factor analysis (CFA). In this study, we examined the internal structure of the MACI in a sample of 1,015 detained adolescent boys (ages 13 to 19). The sample was randomly divided into independent samples. Replication of prior factor models was first attempted in one half (n = 505) of the sample (Sample 1) and disconfirmed these models on the current data. An exploratory factor analysis was then conducted and revealed a 2-factor model representing internalizing and externalizing dimensions. Next, CFA was conducted with Sample 2 (n = 510) and revealed acceptable fit when the model was revised to include correlated error terms among certain scales and factor cross-loadings. Implications for the use of the MACI with adolescents as well as directions for future research are discussed.