Developmental disabilities affect an estimated 6 million Americans. While, as the term developmental suggests, these challenging circumstances begin early in life, the limitations experienced by those with developmental disabilities primarily result from chronic conditions, meaning they will extend indefinitely and may continue throughout a person’s lifetime.

Definition of Developmental Disabilities

From a US legal standpoint, the Developmentally Disabled Assistance and Bill of Rights Act of 2000 defines developmental disability as a “severe, chronic disability” that results in “substantial functional limitations” to three or more major life activities. Under this definition, such limitations are caused by physical and/or mental impairments that manifest in an individual by the age of 22 and require extended, often lifetime assistance, including special services, treatments, and interdisciplinary care.

Causes of Developmental Disabilities

Primarily, developmental disabilities result from chronic disorders and syndromes that exist at birth, or present during early childhood years. Some of the most common in the US are cerebral palsy, autism, Down syndrome, and spina bifida. Other causes of developmental disabilities included fetal alcohol syndrome, brain injuries, and intellectual disabilities or behavior disorders associated with a range of biochemical and cognitive issues.

Substantial Functional Limitations of Developmental Disabilities

The “substantial functional limitations” referred to by the term developmental disability, in this legal context, include three or more major lifestyle skills that most people either acquire at an early age or develop by adulthood. These primarily relate to a person’s ability to provide the sort of self-care required for independent living. In terms of physical impairments, mobility and fine motor skills are major factors to consider, as these prove significant impediments to self-care. However, intellectual abilities, such as being able to communicate and understand language, to be receptive to instruction, and acquire knowledge and skills or equally important considerations when trying to determine whether a person can develop the tools necessary to manage an independent lifestyle, such as economic self-sufficiency.

Developmental Disabilities vs. Delays in Development

While the federal definition of developmental disabilities is crucial to providing an outline for extended and lifelong care for those afflicted, in some cases a developmental disability may be more optimistically viewed as a developmental delay. Because the causes of such physical and mental limitations manifest at an early age, there are times early intervention and treatments, such as occupational therapy, may mitigate the extent an individual requires assistance for varying lifestyle activities. Due to the developmental nature of these limitations, such treatments are often more effective applied early in life, at age five or younger.