The primary aim of the present study was to examine the psychometric properties and measurement invariance of the Inventory of Callous-Unemotional Traits (ICU) self-report and its short version (ICU-12) among a mixed-sex normative sample of 782 Portuguese youth (M = 15.87 years; SD = 1.72). Confirmatory factor analysis revealed that the three-factor structure of the ICU obtained the best fit after the removal of two items, and the two-factor structure of the ICU-12 obtained the best fit after the removal of one item. Cross-sex measurement invariance was demonstrated for both versions of the inventory. The 22-item version of the ICU and its 11-item short form (ICU-SF) demonstrated generally adequate psychometric properties of internal consistency, convergent validity, discriminant validity, and criterion-related validity (e.g., with conduct disorder symptoms). In terms of known-groups validity, males scored significantly higher than females. Results suggest that the use of the ICU and ICU-SF among Portuguese-speaking youth is psychometrically justified.
