Autism spectrum disorders in children with normal intellectual levels: associated impairments and subgroups.

In order to define potential subgroups pertaining to the spectrum of 'high-functioning' pervasive developmental disorders (PDDs) the medical and psychiatric records of 101 children with PDD were reviewed. Ninety-one children had a diagnosis of Asperger syndrome, nine had a PDD not otherwise specified, and one had 'high-functioning' autism. Mean age of the children (71 males, 30 females) was 9 years 8 months (age range 5 to 12 years). Apart from the core dysfunctions of the PDD, i.e. deficient social interaction, communication and repertoires, and restricted interests, 95% had attentional problems, 75% had motor difficulties, 86% had problems with regulation of activity level, and 50% had impulsiveness. About three-quarters had symptoms compatible with mild or severe attention-deficit-hyperactivity disorder (ADHD) or had deficits in attention, motor control, and perception (DAMP), indicating a considerable overlap between these disorders and high-functioning PDD in children of normal or near-normal intelligence. A combination of affective dysregulation, thought disturbance, and severely restricted social interaction, referred to as a multiple complex developmental disorder (MCDD; a condition possibly related to schizoaffective disorder), was recorded in about 8% of the children. Seventeen percent had another major medical diagnosis or medical syndrome, which highlights the importance of completing a neurological assessment of all children with PDDs.