Evaluation of the criterion and convergent validity of the Diagnostic Interview for Social and Communication Disorders in young and low-functioning children.

The Diagnostic Interview for Social and Communication Disorders (DISCO; Wing, 2006) is a standardized, semi-structured and interviewer-based schedule for diagnosis of autism spectrum disorder (ASD). The objective of this study was to evaluate the criterion and convergent validity of the DISCO-11 ICD-10 algorithm in young and low-functioning children. The DISCO-11, Autism Diagnostic Observation Schedule (ADOS), and Social Communication Questionnaire (SCQ) were administered to a Dutch sample of 115 children comprising 52 children with ASD (both with and without intellectual disability), 26 children with intellectual disability (non-ASD), and 37 typically developing children. Results indicated high sensitivity and specificity for DISCO-11 classifications in differentiating ASD from non-ASD according to the clinical classification in children with mild intellectual disability or average intelligence. Among children with a moderate or severe intellectual disability the sensitivity was equally high, but the specificity was significantly lower. The agreement between DISCO-11 and ADOS classifications was substantial, between DISCO-11 and SCQ moderate. The correlations between raw scores of the DISCO and ADOS algorithm or SCQ were both high. In conclusion, the DISCO-11 differentiates accurately between autistic disorder and non-ASD in young children with an average intelligence or mild intellectual disability, but is over inclusive in the lower levels of intellectual disability.