Pervasive Developmental Disorders

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The National Institute of Mental Health (NIMH), a component of the National Institutes of Health (NIH), is a leading federal funder of research on ASD

What are pervasive developmental disorders?

Pervasive developmental disorders (PDD), now known as autism spectrum disorder (ASD), are characterized by delays in the development of social and communication skills. Parents may note symptoms as early as infancy, although the typical age of onset is by 3 years of age.

Symptoms may include:

  • Problems with using and understanding language
  • Difficulty relating to people, objects, and events
  • Different modes of playing with toys and other objects
  • Difficulty with changes in routine or surroundings
  • Repetitive body movements or behavior patterns

Children with PDD vary widely. Some children do not speak at all, while others speak in limited phrases or conversations, and some have relatively average language development. Repetitive play skills and limited social skills are generally evident. Extreme responses to sensory information, such as loud noises and lights, are also common.

There is no known cure for PDD. Medications may be used to address specific behavioral problems and therapy should be specialized according to the needs of each child. Some children with PDD benefit from specialized classrooms and others function well in standard special education classes or regular classes with additional support.

Early intervention plays a critical role in improving the outcome of individuals with PDD.

Learn About Clinical Trials
Clinical trials are studies that allow us to learn more about disorders and improve care. They can help connect patients with new and upcoming treatment options.

How can I or my loved one help improve care for people with pervasive developmental disorders?

Consider participating in a clinical trial so clinicians and scientists can learn more about PDD and related disorders. Clinical research uses human volunteers to help researchers learn more about a disorder and perhaps find better ways to safely detect, treat, or prevent disease.

All types of volunteers are needed—those who are healthy or may have an illness or disease—of all different ages, sexes, races, and ethnicities to ensure that study results apply to as many people as possible, and that treatments will be safe and effective for everyone who will use them.

For information about participating in clinical research visit NIH Clinical Research Trials and You. Learn about clinical trials currently looking for people with PDD at

Where can I find more information about pervasive developmental disorders?

Information may be available from the following resources:

American Speech-Language-Hearing Association (ASHA)


Learn about related topics

Order publications from the NINDS Catalog
The NINDS Publication Catalog offers printed materials on neurological disorders for patients, health professionals, and the general public. All materials are free of charge, and a downloadable PDF version is also available for most publications.