Introduction to Intellectual and Developmental Disabilities

Abstract

Intellectual disability (ID) is the term used to describe a condition defined by limits in cognitive and adaptive abilities that affect function and initially manifest before 18 years of age. This term supplanted the earlier term ‘mental retardation’ within the past two decades. The term developmental disability (DD) was coined de novo in the 1970s when the Developmental Disabilities Act of the US Congress was passed. While an ID is determined by formal psychometric testing to assess the intelligence quotient and adaptive functioning, the term DD is more generic and may include elements of physical limitations in addition to the ID. Both terms are often used interchangeably and have been blended into the term intellectual and developmental disabilities (IDD) to be inclusive for or all individuals who have limitations in cognitive as well as physical functions that are: based on central nervous system dysfunction, manifest in the childhood years, and have lifelong implications. Our goal as members of society is to support and enhance the function of children and adults with IDD and their families and to assure optimal physical, emotional and social well-being in order for them to lead fulfilling lives.