Autistic Disorder: People with autistic disorder have moderate to severe impairments in communication, socialization and restrictive/repetitive behavior.
Asperger Syndrome: People with Asperger Syndrome function in the average to above average intelligence range and have no delays in language skills, but often struggle with social skills and restrictive and repetitive behavior. Asperger's can be diagnosed later in life than other disorders on the spectrum as their typical language development and typical intelligence can make it more difficult to recognize in young children.
Rett Syndrome: Children with Rett syndrome display typical development until approximately five to 30 months and begin to regress, especially in terms of motor skills and loss of abilities in other areas. A key indicator of Rett syndrome is the appearance of repetitive, meaningless hand movements or gestures, and is primarily diagnosed in girls.
Childhood Disintegrative Disorder: Individuals with Childhood Disintegrative Disorder display a significant regression in skills that have previously been acquired. Severe deficits in communication, socialization and/or restrictive and repetitive behavior occur after a period of normal development.
Pervasive Developmental Disorder—Not Otherwise Specified (PDD-NOS): People who do not fully meet the criteria for the other specific disorders but do share the same characteristics with challenges in the areas of social, communication and restrictive/repetitive behaviors are given the diagnosis Pervasive Developmental Disorder—Not Otherwise Specified.