A Validation Study of the Korean Version of Social Communication Questionnaire

：A total of 166 subjects with ASD and their 186 unaffected siblings were recruited through child psychiatry clinics of university hospitals. Board certified child psychiatrists screened all probands suspected to have ASD based on the Diagnostic and Statistical Manual of Mental Disorders, fourth edition. To confirm the diagnoses, the Korean versions of the Autism Diagnostic Ob-servation Schedule and the Autism Diagnostic Interview-Revised (K-ADI-R) were administered to all the subjects. All parents com-pleted the K-SCQ and Social Responsiveness Scale (SRS). The non-ASD siblings were evaluated with the same instruments as the probands with ASD. We performed a factor analysis to examine the structure of K-SCQ. For testing the validity of K-SCQ, we com-pared the difference in Lifetime and Current scores of probands with ASD and their non-ASD siblings using t-test and analysis of covariance. Correlations between the K-SCQ and other measurements of ASD symptomatology, including K-ADI-R totals and do-main scores and SRS, were examined. Receiver operation characteristic curve analysis was performed to extract cutoff scores dis-criminating affection status.