Objectives: To test the extent to which the ICU measures a construct above and beyond ASD trait severity. To identify the proportion of an ASD sample who are regarded as having psychopathic tendencies (as measured by the ICU) in order to inform appropriate cut offs for ICU in an ASD population.
Methods: Cross-sectional data were examined for 56 (87.5% males) young people. A well-standardised parent report interview (3Di) was used to measure ASD. Parent and teacher report SDQ scores for conduct problems were also captured. The Inventory of Callous-unemotional Traits (ICU) parent and teacher scores were used to measure CU traits.
Results: Correlation analysis indicates a relationship between parent reported measures of ASD severity and CU traits (Social reciprocity r =.56, df = 55, p <.05; Communication r =.40, df = p <.05; Repetitive behaviours r = .22, df = 55, p =.11, ns). However, the relationship between ASD and teacher reported CU traits is not indicated (Social reciprocity r =.084, df = 55, p =.54, ns; Communication r = -.09, df = 55, p =.50, ns; Repetitive behaviours r = -.04, df = 55, p =.79, ns). The proportion of young people with ASD reported to have CU traits (>33 on ICU) was higher than the general population (Parent report CU = 58.9%; Teacher report CU =42.9%). CD symptoms were reported in a significantly lower proportion of the sample (Parent report CD = 17.9%; Teacher reported CD = 12.5%).
Conclusions: Using gold-standard CU trait measures in an ASD clinical sample probably leads to a significant over-reporting of CU traits. This could be partially explained by the strong relationship between ASD severity and CU traits, which may reflect conceptual and phenotypic overlap between these two constructs. Cut offs for the ICU need to be modified for an ASD population; and different items may be needed to accurately identify CU traits in the ASD population. Clinicians and researchers should be cautious using the ICU to measure CU traits in ASD populations.
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See more of: Symptoms, Diagnosis & Phenotype