The Signposting Questionnaire for Autism-2 (SQ-A-2): using input from autistic adults to inform questionnaire development

Brief questionnaires help clinicians to identify people who may require in-depth assessment for Autism Spectrum Disorder (hereafter autism) and also facilitate research. However, many current questionnaires do not map onto the latest DSM-5 criteria for autism and were developed by researchers and/or clinicians, with limited input from autistic people. The Signposting Questionnaire for Autism (SQ-A) is a caregiver-report questionnaire for measuring autism signs in children, based on DSM-5 criteria. Here, we developed a revised lifespan version, the SQ-A-2, with input on wording from autistic adults. We tested the SQ-A-2 as a self-report measure in autistic and non-autistic adults, and assessed the impact of the adapted wording on both the psychometric properties and the acceptability of the measure. The SQ-A, containing highly discriminating DSM-5 items from a valid clinical interview, was revised to form the 18-item SQ-A-2, with self- and informant-report options. Following input from a team of four autistic consultants and six autism professionals, item wording on the SQ-A-2 was adapted, thus forming Original and Adapted versions. Subsequently, a sample of autistic and non-autistic adults (N = 302), matched on age, sex, and general cognitive ability, completed both versions of the new SQ-A-2, as well as the widely-used 10-item Autism-Quotient (AQ-10). Autistic participants also rated their preferences for Original versus Adapted items, and provided qualitative responses for their reasoning. Overall, the self-report version of the SQ-A-2 demonstrated excellent internal reliability and convergent validity with the AQ-10, and autistic adults scored significantly higher than non-autistic adults. This group difference was greater for the Adapted compared to the Original version of the SQ-A-2, suggesting autistic consultation may facilitate the development of clinically-useful measures. Additionally, autistic participants preferred the wording of the Adapted versus Original items, both quantitatively and qualitatively. Our findings may not generalise to autistic people with intellectual disability. Ethnicity data was not collected. The adapted version of the SQ-A-2 has the potential to be a valid, clinically useful questionnaire for measuring DSM-5 signs of autism across the lifespan. Our findings also highlight the utility of incorporating autistic input into measure development. Further psychometric testing of the SQ-A-2 in larger, more diverse samples, including the informant-report version, is now required.