Sometimes a child with learning and behavioral differences doesn't meet all the diagnostic criteria for Autism, which led to a diagnosis of PDD-NOS. Pervasive Developmental Disorder - Not Otherwise Specified is the diagnosis that was given to those who fell into this category and were generally considered to exhibit milder symptoms than those with Autism Spectrum Disorder.
- Atypical or inappropriate social behavior
- Uneven skill development (motor, sensory, visual-spatial organizational, cognitive, social, academic, behavioral)
- Poorly developed speech and language comprehension skills
- Difficulty with transitions
- Deficits in nonverbal and/or verbal communication
- Increased or decreased sensitivities to taste, sight, sound, smell and/or touch
- Perseverative (repetitive or ritualistic) behaviors (i.e., opening and closing doors repeatedly or switching a light on and off )
As of 2013, PDD-NOS and Asperger Syndrome were both included under the umbrella of Autism Spectrum Disorder (ASD). Prior to 2013, some practitioners referred to PDD-NOS as "atypical autism" or believed it to be a milder form of autism spectrum disorder. This debate among professionals concerning exactly how to classify those who don't meet all the criteria for Autism led to much confusion among parents about the diagnosis. A child may have received a diagnosis of PDD-NOS if he or she fell into the following categories:
- The child is high-functioning but is experiencing mild cognitive issues and/or language delay that would prevent an Asperger diagnosis.
- The child is similar to a person with Autism but symptoms began at a late age.
- The child has many symptoms of Autism but has fewer perseverative behaviors than those with an Autism diagnosis.