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Pervasive Developmental Disorder-Not Otherwise Specified (PDD-NOS)

What is Pervasive Developmental Disorder-Not Otherwise Specified (PDD-NOS)?

Pervasive Developmental Disorder-Not Otherwise Specified (PDD-NOS) is a neurological disorder that may fall under the umbrella terms of Pervasive Developmental Disorder or Autistic Spectrum Disorder. PDD-NOS can often be referred to as Atypical Autism. It refers to individuals who do not meet the diagnostic criteria for any of the four other pervasive developmental disorders, but show signs of unusual development in communication, social interaction and interests. Individuals with PDD-NOS will have some symptoms of one pervasive developmental disorder, but not enough to receive a specific diagnosis.

Symptoms experienced can range from mild to severe, and no two people diagnosed with PPD-NOS will have the exact same symptoms. However, common characteristics include:

  • Poorly developed skills in speech and language comprehension
  • Deficits in social behaviour
  • Uneven skill development
  • Poor nonverbal communication
  • Unusual responses to sensory input, such as taste, smell, touch, sound
  • Repetitive behaviours
  • Obsessive tendencies

The causes of PDD-NOS are currently not known. Research has suggested that the cause may be due to genetic and environmental factors that affect the brain's function; however the exact biological mechanisms are not clear.

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