Reciprocal social behavior in children with and without pervasive developmental disorders

An invariant feature of pervasive developmental disorders (PDDs) is a relat ive deficit in the capacity for reciprocal social behavior (RSB). The autho rs acquired teacher reports of RSB in 287 schoolchildren and parent reports of RSB in 158 child psychiatric patients using a new research instrument, the Social Reciprocity Scale. Total scores on this measure of RSB were cont inuously distributed in all groups of subjects; children with PDDs scored s ignificantly higher for the degree of deficits in RSB than did clinical or nonclinical controls. Latent class analysis and factor analysis failed to d emonstrate separate categories of deficiency for core autistic symptomatolo gy and more general impairments in RSB, consistent with the notion of a "br oader autism phenotype." Assessments of RSB on a continuous scale may be us eful clinically for characterizing the behavior of children whose social de ficits fall below the threshold for a full diagnosis of autism. They may al so be useful in genetic-linkage studies of autistic spectrum disorders.