Video The Autism Diagnosis ABA Training Video Autism is a general term used to describe a constellation of complex developmental disorders known as Pervasive Developmental Disorders (PDD). PDD is like an umbrella with all of the other related disorders associated with it, falling underneath. Some people also refer to this as the Autism Spectrum. Autistic Disorder Asperger’s Syndrome Rett Syndrome Childhood Disintegrative Disorder Pervasive Developmental Disorders – Not Otherwise Specified (PDD-NOS) Diagnostic Criteria Autism is defined in the DSM-IV-TR as exhibiting at least six symptoms from the following three categories. Marked impairment in verbal and non-verbal communication. Engagement in repetitive or stereotypic movements, phrases, or movements of objects. Qualitative impairment in social interactions.