ABSTRACT
Pervasive developmental disorders (PDDs) are severe psychiatric disorders, with onset in the first 3 years of life, which typically determine marked impairments in reciprocal social interaction, communication, and cognitive development. Stereotyped behavior, interests, and activities are shared, in different ways and intensities, by the five subtypes of PDDs, that is autistic disorder, the prototypical disorder, Asperger syndrome, Rett syndrome, childhood disintegrative disorder, and PDD not otherwise specified (PDDNOS) (American Psychiatric Association, 2000).
