How well can commonly used anxiety scales detect treatment outcomes in the context of autism?

Anxiety is one of the most prevalent mental health challenges in autistic children, yet there is limited evidence on effective tools to measure treatment outcomes. Previous research with non-autistic children has found that the Child Anxiety Impact Scale, Parent Version achieved good diagnostic accuracy when measuring treatment outcomes and performed better than a commonly used symptom measure. However, this has not been evaluated for autistic children. The present study examined the psychometric properties of the Child Anxiety Impact Scale, Parent Version in autistic children and compared its utility against other anxiety symptom measures, to detect treatment outcomes as assessed by a gold-standard diagnostic interview, the Anxiety and Related Disorders Interview Schedule, Child Version, Parent Interview with the Autism Spectrum Addendum. Data were used from 212 children (aged 7-13 years) who participated in a randomised controlled trial. Receiver-operating characteristic curve analyses were conducted, and subsequent subgroup analyses were conducted using DeLong tests. Results demonstrated that the Child Anxiety Impact Scale, Parent Version had strong psychometric properties, with total scores significantly outperforming other measures in predicting post-treatment recovery from anxiety diagnoses. These findings have implications for future choices of treatment outcome measures in research and clinical practice.Lay abstract The importance of having valid and reliable anxiety measures for autistic children has been highlighted as a research priority by professionals and people with lived experience. Yet, while anxiety has been frequently assessed in autistic children, we do not currently know much about how well commonly used anxiety measures work, especially parent reports, in this context. This has significant implications for care planning and resource allocation for autistic children who experience significant anxiety problems. The research team studied data collected in a previously published multi-centred randomised controlled trial (RCT) testing an adapted cognitive behavioural therapy for anxiety (Wood et al., 2020) to better understand how different anxiety measures did, compared to gold-standard anxiety diagnostic assessments, in detecting treatment outcomes. They focused in particular on the Child Anxiety Impact Scale, Parent Version (CAIS-P). This study found that the CAIS-P did better than conventional anxiety symptom measures in detecting treatment outcomes for anxiety problems in autistic children. This study adds to the current evidence base to inform choices of measurement of anxiety problems in the context of autism.