The development of normal and autistic children: a comparative study.

This study tests the hypothesis that the development of normal and autistic children differs only in rate and asymptote. A total of 195 normal children between 1 and 5 years of age, 160 normal children between 3 months and 24 months of age, and 41 autistic children between 5 and 11 years of age were evaluated on the eight psychological variables constituting the Behavioral Rating Instrument for Autistic and other Atypical Children (BRIAAC). While many similarities were found, there were a sufficient number of differences to justify DMS-III's statement that certain autistic behaviors are not normal at any stage of development. Differences were particularly prominent when the development of normal infants was compared with that of severely disturbed autistic children. In general, the issue of whether deviant development differs only quantitatively from normal development can best be decided on the basis of developmental data and by utilizing instruments that sample all the major characteristics of both populations.