What are developmental disabilities?

Developmental disabilities encompass a broad range of conditions that result from cognitive and/or physical impairments. They are identified before the age of 22, and usually last throughout a person’s lifetime. These disabilities include intellectual disabilities, cerebral palsy, autism spectrum disorder, Down syndrome, language and learning disorders, vision impairment, and hearing loss.

What are the most common developmental disabilities?

The most common developmental disability is intellectual disability. Cerebral palsy is the second most common developmental disability, followed by autism spectrum disorder. Other developmental disabilities may include:

  • Attention-Deficit/Hyperactivity Disorder
  • Angelman Syndrome
  • Bipolar Disorder
  • Central Auditory Processing Disorder
  • Down Syndrome
  • Expressive Language Disorder
  • Fragile X Syndrome
  • IsoDicentric 15
  • Landau-Kleá°€ner Syndrome
  • Learning Disabilities
  • Neural Tube Defects
  • Phenylketonuria
  • Prader-Willi Syndrome
  • Seizure Disorders
  • Tourette Syndrome
  • Traumatic Brain Injury
  • Williams Syndrome


How prevalent are developmental disabilities?

Developmental disabilities occur in people of all racial, ethnic, educational, and socioeconomic backgrounds. According to the Centers for Disease Control and Prevention, approximately one in six children (or 15 percent of children under the age of 18) are affected. It is estimated that more than five million Americans have developmental disabilities.

How are developmental disabilities diagnosed?

If you are concerned that a member of your family may have a developmental disability—whether physical or intellectual—contact a respected behavioral healthcare organization and/or healthcare professional. First, the organization should have a qualified professional give your family member standardized intelligence and skills tests. Second, the professional should determine your family member’s strengths and weaknesses in the areas of intellectual and adaptive behavior skills, psychological and emotional considerations, physical health, and environmental factors. Finally, a trained interdisciplinary group of professionals should meet to determine what supports are needed to address each of the areas stated above.

What services are available to someone with a developmental disability?

After the special needs of a person with a developmental disability have been evaluated, we recommended strategies, services, and supports to optimize individual functioning. Availability, eligibility guidelines, and funding of services will vary from state to state. These may include educational, residential, vocational, and day habilitation services. These services help individuals lead more independent lives in their communities.

Download the pdf.

Additional resources

Association on Intellectual and Developmental Disabilities (

ARC of the United States (

Centers for Disease Control and Prevention (