Predictive Relations Between Early Adversity, Nonlinear Trajectories of Hypothalamic–Pituitary–Adrenal Axis Functioning, and Later Callous-Unemotional Traits

Developmental pathways to callous-unemotional (CU) traits are heterogeneous, with early social experiences and stress physiology, such as hypothalamic–pituitary–adrenal (HPA) axis functioning, likely playing key roles. However, few studies have examined how adversity and HPA axis functioning in early childhood relate to later CU traits. Using Latent Basis Growth Mixture Modeling with a longitudinal sample (N = 1,292), we examined relations between trajectories of salivary basal cortisol in early childhood (6, 15, 24, and 48 months), adversity at 6 months, and CU traits at preadolescence (M_age = 13.22, SD = 0.62 years, range = 12.52–15.68 years). Results revealed a low-stable basal cortisol class (class 1, ~ 95%) and an unstable class (class 2, ~ 5%) transitioning from high to low cortisol. Class 2 had significantly higher levels of CU traits at preadolescence than class 1. Early adversity at 6 months predicted CU traits in class 2. These findings identify a specific physiological pattern under which early adversity relates to later CU traits.