Protective Factors

Intellectual disability refers to functional limitations starting in childhood resulting from lower intelligence and difficulties learning adaptive behaviors, or those practical and social skills typically acquired through one’s daily experiences. The prevalence of intellectual disability in the general population in the United States and other similar developed countries is approximately 1 to 2% and has remained stable over several decades. In the vast majority of affected individuals, the level of disability is mild. Although the underlying etiology of intellectual disability remains unknown in the case of many individuals, several factors affect one’s risk of developing intellectual disability and its subsequent severity, including gender and race, genetics, environmental exposures, and social contexts. Their contributions are further discussed throughout this entry.