On the differential diagnosis of autism spectrum disorder and attention-deficit/hyperactivity disorder

This study evaluated whether a parent-as-respondent measure, the Coolidge Autistic Symptom Survey (CASS-84), could differentiate among children with mild, moderate, or severe autism spectrum disorder (ASD), children with attention-deficit/hyperactivity disorder (ADHD), and children developing typically. A total of 201 parents were recruited on Amazon's Mechanical Turk to complete the CASS-84 regarding their child (5–17 years old) and reported their children's diagnosis as either ASD (severity), ADHD, or developing typically. Parents also completed an 18-item scale of ADHD symptoms. A one-way analysis of variance demonstrated that the CASS-84 successfully differentiated ASD, ADHD, and typical development, but could not differentiate between mild and moderate forms of ASD, nor mild ASD from ADHD. The present results warrant further investigation with larger samples.