Social behaviour in pervasive developmental disorders: effects of informant, group and "theory-of-mind".

Theory of mind skills and a range of social behaviour in everyday life were assessed in a sample of 21 children with pervasive developmental disorders and 22 normally-developing preschoolers. Parents, teachers and therapists were interviewed using the Vineland Adaptive Behaviour Scales and a new supplementary scale, the "Echelle d'Adaptation Sociale pour Enfants" (EASE). Teachers and therapists were able to differentiate subtle forms of social problems in everyday life between subgroups of children diagnosed later to have either autism (n = 13) or PDDNOS (n = 8), according to DSM-III-R (1) criteria. This study offers a (small) cross-cultural replication of recent work suggesting that differences in the mentalising skills of children with autism are reflected in the everyday social behaviour of this group. A significant effect of informant was found for the PDD group, and this effect was particularly pronounced when children with autism were considered separately. The implications of informant differences are discussed.