The utility of parent-report screening tools in differentiating autism versus attention-deficit/hyperactivity disorder in school-age children

Symptoms of autism spectrum disorder and attention-deficit/hyperactivity disorder often co-occur, challenging timely, and accurate diagnosis. We assessed the performance of three parent-report measures in discriminating autism spectrum disorder from attention-deficit/hyperactivity disorder without autism spectrum disorder (ADHD(w/oASD)) in school-age verbally fluent children. We examined the Autism Symptom Interview - School-Age and two widely used parent questionnaires: Social Responsiveness Scale - 2nd Edition and Social Communication Questionnaire - Lifetime. Receiver operating characteristic curves assessed each instrument's performance against the best-estimate clinician Diagnostic and Statistical Manual of Mental Disorders, 5th Edition diagnosis of autism spectrum disorder or of ADHD(w/oASD) (n = 74, n = 102, respectively; 6-11 years). These yielded moderate accuracies: area under the curve = 0.85, 0.79, and 0.78 for Social Communication Questionnaire - Lifetime, Autism Symptom Interview, and Social Responsiveness Scale - 2nd Edition, respectively. Area under the curve pairwise comparisons reached our statistical significance (p < 0.01) for the Social Communication Questionnaire - Lifetime versus the Social Responsiveness Scale - 2nd Edition. Within instruments, sensitivity and specificity varied across autism spectrum disorder cutoffs. Along with the between-instrument variability, this indicates that clinicians and researchers have valid options, depending on the settings and their goals. Comparing children correctly and incorrectly classified as autism spectrum disorder showed no differences in demographics, intellectual abilities, or in any specific clinical profile(s), except for the degree of parent concerns across autism spectrum disorder and comorbid psychopathology-related symptoms. Together, results suggest that complementing parent screeners with multiple sources may be needed to best differentiate school-age verbally fluent children with autism spectrum disorder versus ADHD(w/oASD). Lay abstract We tested the ability of a short, recently developed parent interview and two widely used parent-report questionnaires to discriminate school-age verbal children with autism spectrum disorder from those with attention-deficit/hyperactivity disorder without autism spectrum disorder (ADHD(w/oASD)). These measures included the Autism Symptom Interview - School-Age, the Social Responsiveness Scale - 2nd Edition, and the Social Communication Questionnaire - Lifetime. The classification accuracy of all three parent screeners fell in the moderate range. Accuracy varied by instrument, and the Social Communication Questionnaire - Lifetime questionniare showed the highest accuracy. Children with autism spectrum disorder who were incorrectly classified by all parent screeners did not differ from those correctly classified in regard to demographics, intellectual abilities, nor in any specific clinical area beyond general parent concerns. These findings showed that there are valid screening options for assessing school-age verbal children with autism spectrum disorder versus ADHD(w/oASD). They also underscore the need to assess multiple sources of information for increased accuracy.