Primary and Secondary Callous-Unemotional Childhood Variants in a Korean Community Sample.

Despite the growing support for the multiple developmental pathways to phenotypic callous-unemotional (CU) traits (i.e., primary, and secondary CU variants), there remains limited research on childhood manifestations of CU variants in non-Western, community samples. Using a latent profile analysis with data sourced from the longitudinal, nationwide Korean sample (N = 1597, 48.7% girls), we discerned heterogeneous groups of children, based on externalizing problems, CU traits, and emotional reactivity level. The optimal five-profile solution identified distinct subgroups: low-risk, primary CU (characterized by low emotional reactivity and externalizing problem), reactive (low CU/moderate emotion reactivity and externalizing problem), and two secondary CU groups (i.e., secondary-high CU and secondary-moderate CU; both high in emotional reactivity and externalizing problems). The two secondary CU variants demonstrated differences from the primary CU variants, in that both are high in preschool externalizing problems (age 6) and school-age conduct problems (age 11). However, the secondary-moderate CU group displayed greater levels of anxiety at age 11 compared to secondary-high CU, indicating divergent developmental trajectories of secondary CU variants. These findings expand our understanding of CU variants among Korean preschoolers and highlight the role of emotional reactivity in distinguishing such subtypes and identifying their developmental outcomes across time.