Measurement invariance of the parent-reported Strengths and Difficulties Questionnaire in autistic adolescents.

Lay abstract: Autistic people are more likely than non-autistic people to experience mental health difficulties. The Strengths and Difficulties Questionnaire is often used to screen for these difficulties and to otherwise make important decisions about mental health treatment and research in populations of autistic people. However, this study suggests that parent-reported Strengths and Difficulties Questionnaire scores may not be useful for comparing autistic and non-autistic adolescents at 11, 14 and 17 years old, as well as screening for mental health conditions in autistic adolescents. In addition, several items may be more likely to be endorsed by parents of autistic 17-year-olds than by parents of non-autistic 17-year-olds (and vice versa), which might suggest caution is needed when comparing groups on specific items.