What is a Developmental Disability? "Developmental Disability" means: A severe, chronic disability of an individual that: Is attributable to an intellectual or physical impairment or combination of intellectual and physical impairments. Is manifested before the individual reaches age 22. Is likely to continue indefinitely. Results in substantial functional limitations in three (3) or more of the following areas of major life activity: Self-care. Receptive and expressive language. Learning. Mobility. Self-direction. Capacity for independent living. Economic self-sufficiency. Is not attributed solely to mental illness.