Associations among externalizing psychopathology, personality, and behavioral traits: Models of an externalizing spectrum in youth.

Consistent evidence has documented the cross-sectional and longitudinal associations of externalizing psychopathology with personality and behavioral traits, suggesting the presence of a broad, underlying liability to externalizing. In one of the first studies of its kind, we use a large, representative sample of youth (N = 2,245 twins and their siblings) to evaluate the evidence of an externalizing spectrum model, which includes psychopathology, personality, and behavioral traits and spans normal and pathological variation. We examine evidence for the inclusion of 15 candidate traits, from the domains of general and pathological personality, temperament, and aggression, in a model that includes dimensions of common childhood externalizing psychopathology. Using a combination of structural equation modeling and item response theory analyses, we found strong to moderate evidence for including the narcissism and impulsivity dimensions of psychopathic traits; reactive, proactive, and relational aggression; and agreeableness and conscientiousness from the five-factor model of personality. These traits were reliable indicators of the externalizing spectrum, as evidenced by their shared variance with externalizing symptoms, strong factor loadings, and high information. In addition, these traits indexed the externalizing spectrum at higher and lower levels of the latent trait relative to the symptoms alone, highlighting the value of including them. Many of our findings replicate and extend work conducted in adult samples, suggesting developmental continuity of externalizing. Broadly speaking, these findings have important implications for the conceptualization, measurement, and treatment of externalizing in youth. (PsycInfo Database Record (c) 2025 APA, all rights reserved).