A diagnosis of Pervasive Developmental Disorder - Not Otherwise Specified (PDD-NOS) is reserved for children who have many autistic-like symptoms, but don’t quite fit into the “box” for the other autism spectrum disorders. For example, their symptoms might have started after the age of three, or they may demonstrate repetitive behaviours and abnormal speech, but have better social skills than other autistic children. In some cases, a diagnosis of PDD-NOS is eventually changed to something else as the child gets older and the symptoms become clearer.