The Strengths and Difficulties Questionnaire self-report-, parent-, and teacher version in children with intellectual and developmental disabilities

Background: The Strengths and Difficulties Questionnaire (SDQ) is a frequently used behavioral screening instrument. However, its psychometric properties have been rarely examined among children with intellectual and developmental disabilities (IDD). Aims: The main aims of this study were to examine the internal consistency (i.e., McDonald’s Omega), the convergent validity (by correlating the Total difficulties score with the Aberrant Behavior Checklist [ABC]), the divergent validity (by correlating the Total difficulties score with the Vineland Adaptive Behavior Composite; VABS-II Total) and the factorial validity (by the means of confirmatory factor analyses [CFA]) of the SDQ self-report-, parent-, and teacher version in a sample of children with IDD. Method: Participants were 365 children and adolescents (males n = 238; 65 %) aged 4–18 years (M = 10.11, SD = 3.82) referred for a developmental/neurological assessment to the neuropediatric outpatient clinics in the specialist health services. The SDQ was filled inn by 115 children, 337 parents, and 248 teachers. Results: McDonald’s Omega was overall lowest for the self-report version. Correlations of the SDQ Total difficulties score and the ABC subscales were strongest for the parent version. The results of the CFA indicated best model fit for the six-factor model that included a method factor for all three versions of the SDQ, however, model fit was overall not good. Conclusions: Further research that examines the psychometric properties of the SDQ among multiple informants in large samples of children with IDD is needed