top of page

What is IDD?


IDD stands for Intellectual and Developmental Disability. The term may have slightly different definitions depending on the context. The American Association of Intellectual and Developmental Disabilities defines "Developmental Disabilities" as an umbrella term that includes intellectual disability, but also includes other disabilities that are apparent during childhood. Developmental disabilities are severe chronic disabilities that can be cognitive, physical or both. The disabilities appear before the age of 22 and are likely to be lifelong. Some developmental disabilities are largely physical issues, such as cerebral palsy or epilepsy. Some individuals may have a condition that includes a physical and intellectual disability, for example, Down syndrome or fetal alcohol syndrome. Intellectual disability encompasses the “cognitive” part of this definition, that is, a disability that is broadly related to thought processes. There are three major criteria for intellectual disability: significant limitations in intellectual functioning,  significant limitations in adaptive behavior, and onset before the age of 18. Because intellectual and other developmental disabilities often co-occur, intellectual disability professionals often work with people who have both types of disabilities.

Colorado's Definition

Colorado, like all states, defines "developmental disability" for service eligibility purposes. According to state law, persons with a developmental disability are those who have a "disability that is manifested before the person reaches twenty-two years of age, which constitutes a substantial disability to the affected individual, and is attributable to mental retardation or related conditions which include cerebral palsy, epilepsy, autism or other neurological conditions when such conditions result in impairment of general intellectual functioning or adaptive behavior similar to that of a person with mental retardation" (CRS 27-10.5-102).  For children under five, eligibility is based on determination of either a developmental delay or factors putting the child at risk of having a developmental disability. Colorado's regulatory definition can be found at 10 CCR 2505-10 8.600.4. 

Federal Definition

As defined in the Developmental Disabilities Assistance and Bill of Rights Act (P.L. 106-402), the term “developmental disability” means a severe, chronic disability of an individual that:


(A) is attributable to a mental or physical impairment or combination of mental and physical impairment;

(B) is manifested before the individual attains age 22;

(C) is likely to continue indefinitely;

(D) results in substantial functional limitations in 3 or more of the following areas of major life activity: (i) self-care; (ii) receptive and expressive language; (iii) learning; (iv) mobility; (v) self-direction; (vi) capacity for independent living; and (vii) economic self-sufficiency; and

(E) reflects the individual’s need for a combination and sequence of special, interdisciplinary, or generic services, individualized supports, or other forms of assistance that are of lifelong or extended duration and are individually planned and coordinated.


An individual from birth to age 9, inclusive, who has substantial developmental delay or specific congenital or acquired conditions may be considered to have a developmental disability without meeting 3 or more of the criteria described above in (A) through (E) if the individual, without services and supports, has a high probability of meeting those criteria later in life.

bottom of page