Heterogeneity in externalizing problems at age 3: Association with age 15 biological and environmental outcomes.

Investigating heterogeneity in antisocial behavior early in life is essential for understanding the etiology, development, prognosis, and treatment of these problems. Data from the longitudinal National Institute of Child Health and Development (NICHD) study of Early Child Care were used to identify homogeneous groups of young antisocial children differentiated on externalizing problems, internalizing problems, and callous-unemotional (CU) traits using latent profile analysis (LPA). We examined how identified subgroups were differentiated on adolescent social, biological, cognitive, and environmental outcomes, controlling for dispositional and contextual antecedents during the first 2 years of life. The sample consisted of 1,167 children (52% male) followed from toddlerhood to adolescence. LPA identified a large "low problems" group (n = 795; 49.9% male) as well as 3 antisocial groups at age 3: the first scored high on internalizing and externalizing problems but low on CU traits (Ext/Int, n = 125), the second scored high on CU traits and externalizing problems but low on internalizing problems (primary CU variant, n = 135), and the third scored high on CU traits, internalizing, and externalizing problems (secondary CU variant, n = 112), and these differences persisted into adolescence. Primary and secondary CU variants were further differentiated from one another on adolescent measures of aggression (reactive and relational), biological indices (cortisol, heart rate), cognitive abilities, and parental psychopathology, after controlling for early life risk factors (i.e., maternal sensitivity, difficult temperament, and maternal depression). We discuss implications of our findings for research, theory, and practice on early childhood externalizing problems. (PsycINFO Database Record (c) 2017 APA, all rights reserved).