An Overview of Intellectual Disability: Definition, Diagnosis, Classification, and Systems of Supports (12th ed.)

The American Association on Intellectual and Developmental Disabilities (AAIDD) has published terminology and classification manuals since 1921. Their goals over the last 100 years have been consistent: To fulfill the Association's continued responsibility to be the primary repository of intellectual disability-related research and best practices; to publish a scientific definition of intellectual disability (ID) and its assumptions based on research and one that provides a long, stable definitional history; to provide a singular focus on ID and the lives of people with ID and their families; and to communicate professional standards, ethics, and best practices regarding diagnosis, classification, and planning supports. Consistent with these historical goals, the goals of the 12th edition of the AAIDD manual (Schalock et al. 2021) are to: (a) integrate material published in the 11th edition (Schalock et al., 2010) of the AAIDD manual with post-2010 developments and historical markers; (b) develop...