This definition of PDD-NOS is used when a severe and pervasive  impairment is discovered in the development of reciprocal social interaction or verbal and nonverbal communication skills.  It is also used when stereotyped behavior, interests, and activities are present, but the criteria are not met for a specific Pervasive Developmental Disorder, Schizophrenia, Schizotypal Personality Disorder or Avoidant Personality Disorder. The criteria has not been met because of the age of onset, unusual symptomatology, subthreshold symptomatology, or, perhaps, all of these.

To learn more about PDD-NOS click here.