pervasive developmental disorder (PDD), term historically used in reference to any of a group of conditions characterized by early-childhood onset and varying degrees of impairment of language acquisition, communication, social behavior, and motor function. In 2013 pervasive developmental disorders (PDDs) were reclassified as autism spectrum disorders (ASDs).
Five types of PDDs were once recognized: autism, Asperger syndrome, pervasive developmental disorder not otherwise specified (PDD-NOS), childhood disintegrative disorder (CDD), and Rett syndrome. Most PDDs were characterized by deficits in a child’s ability to interact socially and by one or more instances of atypical childhood development.