What is a Developmental Disability?

Intellectual Disability, Cerebral Palsy, Epilepsy, and Autism


A developmental disability is defined in state and federal law as intellectual disability, cerebral palsy, epilepsy, and autism. Other substantially disabling conditions closely related to intellectual disability or which require treatment similar to the treatment required by persons with intellectual disability may be eligible for services. The onset of these conditions had to have been prior to age 18,  continues or can be expected to continue indefinitely and constitutes a substantial handicap for the individual.

An infant or young child under age three may be found eligible for the Early Start program if they have a developmental delay, have an established risk condition or meet criteria as a high risk infant (due to medical problems and complications, or because one or both parents has a developmental disability). For more information on eligibility for infants and toddlers up to age 3 years, go to Early Intervention.

A substantial disability:

  • is a condition which results in major impairment of cognitive and/or social functioning, representing sufficient impairment to require interdisciplinary planning and coordination of special or generic services to assist the individual in achieving maximum potential; and
  • must cause significant functional limitations, as determined by the regional center, in three or more of the following areas of major life activity, as appropriate to the person’s age.  Since an individual’s cognitive and/or social functioning are many-faceted, the existence of a major impairment shall be determined through assessment(s) in the following areas of daily life activity:
    • Receptive and expressive language;
    • Learning;
    • Self-care;
    • Mobility;
    • Self-direction;
    • Capacity for independent living;
    • Economic self-sufficiency

A Developmental Disability shall not include handicapping conditions that are:

  • Solely psychiatric disorders where there is impaired intellectual or social functioning which originated as a result of the psychiatric disorder or treatment given for such a disorder. Such psychiatric disorders include psycho-social deprivation and/or psychosis, severe neurosis or personality disorders even where social and intellectual functioning have become seriously impaired as an integral manifestation of the disorder
  • Solely learning disabilities. A learning disability is a condition which manifests as a significant discrepancy between estimated cognitive potential and actual level of educational performance and which is not a result of generalized mental retardation, educational or psycho-social deprivation, psychiatric disorder, or sensory loss
  • Solely physical in nature. These conditions include congenital anomalies or conditions acquired through disease, accident, or faulty development which are not associated with a neurological impairment that results in a need for treatment similar to that required for mental retardation. Some examples are polio, muscular dystrophy, arthritis.