Use of gilliam aspergers disorder scale in differentiating high and low functioning autism and ADHD

Little is known about the validity of Gilliam Aspergers Disorder Scale (GADS), although it is widely used. This study of 199 children with high functioning autism or Aspergers Disorder, 195 with low functioning autism, and 83 with Attention Deficit Hyperactivity Disorder (ADHD) showed high classification accuracy (autism vs ADHD) for clinicians GADS Quotients (92%), and somewhat lower accuracy (77%) for parents Quotients. Both children with high and low functioning autism had clinicians Quotients (M = 99 and 101, respectively) similar to the Aspergers Disorder mean of 100 for the GADS normative sample. Children with high functioning autism scored significantly higher on the Cognitive Patterns subscale than children with low functioning autism, and the latter had higher scores on the remaining subscales: Social Interaction, Restricted Patterns of Behavior, and Pragmatic Skills. Using the clinicians Quotient and Cognitive Patterns score, 70% of children were correctly identified as having high or low functioning autism or ADHD.