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Intellectual and Developmental Disabilities (IDD)

child with intellectual and developmental disabilities

An intellectual disability is made of significant limitations that impact both a person’s intellectual functioning and adaptive behavior.

The disability originates prior to the age of 18. An intellectual disability diagnosis is accompanied by information that describes the severity of the diagnosis. Severity levels include mild, moderate, severe, and profound.

The term developmental disability is used to include multiple diagnoses including intellectual disability.

Other diagnoses include cerebral palsy and Down syndrome. Developmental disabilities are severe and can impact a person’s cognitive ability, physical ability, or both. These disabilities appear before the age of 22 years and often are lifelong.

There is no cure or single treatment for intellectual and developmental disabilities. Each person is unique and has his or her own profile. Instead, treatment and intervention should consider coexisting strengths and needs in all areas and aspects of a person’s life.

American Association on Intellectual and Developmental Disabilities


National Down Syndrome Congress


United Cerebral Palsy