Assessment of anxiety in children and adolescents including children with Autism spectrum disorder

Children and adolescents with Autism Spectrum Disorder (ASD) are at increased risk of anxiety disorders. Current assessment measures used to assess anxiety in children with ASD are standardized for neurotypical children posing a limitation to accurate assessment of anxiety in children with ASD. The aim of this thesis was to assess suitability of a currently used measure to assess anxiety in children and adolescents with ASD as well as to develop a new and improved parent measure to assess anxiety in children and adolescents with and without ASD. The thesis is comprised of two separate papers utilising two different samples (Study 1: N = 426; Study 2: N = 734). In study one, the measurement invariance of the Spence Children’s Anxiety Scale (Parent Form, SCAS-P) in a sample of children with anxiety or ASD was assessed. It was hypothesised that the SCAS-P would perform differently in the ASD population than it did in the anxious population. Study two replicated findings of measurement variance for ASD in the SCAS-P in a new sample and also developed and evaluated a parent report measure for anxiety that will be suitable for clinical and non-clinical populations of children and youth including children with ASD. The newly developed measure, the Macquarie Anxiety Behavioural Scale (MABS) focuses on observable cognitive, behavioural and physiological symptoms of anxiety in children and adolescents including individuals with ASD. A confirmatory factor-analytic approach was used to establish the factor structure of the MABS and assess measurement invariance of the SCAS-P and MABS across a group of children with anxiety and ASD in Study 1 and a different group of children with and without ASD in Study 1. Both studies demonstrated measurement variance (difference) for both the SCAS-P and the MABS indicating that at least parts of both parent measures cannot be interpreted in the same way in an ASD population compared to typically developing children. The findings build upon a growing body of evidence which indicates that anxiety may present differently in young people with ASD compared to typically developing children and youth. Future research can utilise findings from the present studies to refine and further develop an assessment measure that will be useful for children and adolescents including children with ASD.