Reference Values of the Inventory of Callous-Unemotional Traits in Youth Populations: A Systematic Literature Review.

Callous-unemotional (CU) traits are directly related to psychopathic traits, as they are based on features such as emotional insensitivity, lack of empathy, and lack of remorse. These traits typically develop during childhood and adolescence. Identifying them is extremely important, as they are predictors of antisocial behavior and the potential development of psychopathic traits in adulthood. The Inventory of Callous-Unemotional Traits (ICU) has been widely used to measure callous-unemotional traits in children and adolescents. A systematic literature review was conducted to establish reference values for the ICU in these age groups. Using specific inclusion and exclusion criteria, relevant studies were identified through databases and manual searches. The review included articles with empirical and quantitative methodologies. A total of 297 studies were included. Across regions, ICU scores were consistently higher in clinical, Disruptive Behavior Disorder-diagnosed, and forensic samples than in community samples, supporting the role of CU traits as markers of elevated psychopathological risk. Subscale analyses showed that Callousness and Uncaring more reliably differentiated high-risk groups than the Unemotional subscale. Substantial regional variation was observed, with particularly elevated community scores in Asian samples and broadly comparable forensic scores across Western regions. ICU scores vary systematically by sample type, region, and subscale, underscoring the importance of context-sensitive interpretation. The pooled reference values provided in this review offer an empirical framework for comparative and clinical interpretation of ICU scores in the absence of standardized norms or cutoffs.