Structural validity of the MACI psychopathy and narcissism scales: evidence of multidimensionality and implications for use in research and screening.

This study investigated the psychometric properties and predictive validity of three self-report scales (the Psychopathy Content Scale, the Psychopathy-16 scale, and the Egotistic scale) derived from the Millon Adolescent Clinical Inventory (MACI) to screen for the presence of psychopathic and narcissistic personality characteristics. Exploratory and confirmatory factor analyses were performed in a sample of 173 clinic-referred adolescents (ages 12-17), results from which suggested that these scales are multidimensional in nature. The Psychopathy Content Scale was best captured by a two-factor structure, with personality-based items loading on one factor and antisocial/impulsive behaviors loading on the second. The most parsimonious solution for the Psychopathy-16 scale was a three-factor model, characterized by callous and egocentric features on the first two factors and antisocial behaviors on the third. The Egotistic scale of the MACI was best represented by three factors, depicting features of self-confidence, exhibitionistic tendencies, and social conceit, respectively. Regression analyses supported the multidimensionality of these scales by showing divergent patterns of association with violent and nonviolent outcomes among the factors that composed the scales.