Follow-up of children diagnosed with pervasive developmental disorders: stability and change during the preschool years.

Forty-one children with pervasive developmental disorders (PDDs) receiving eclectic services were assessed twice during their preschool years. Measures were compared over time for the whole group and for diagnostic subgroups: Childhood autism (CA group) and Other PDDs group. The mean intelligence quotient/developmental quotient (IQ/DQ) of the whole group was stable (P = 0.209) and scores on the Childhood Autism Rating Scale (CARS) decreased (P = 0.001). At time 2, the CA group was more impaired than the other PDDs group: autistic symptoms were more severe (P = 0.01), adaptive behavior scores were lower (P = 0.014), and a trend for lower IQ/DQs (P = 0.06). Children in this study seemed to fare better than reported in previous follow-up studies on children with autism.