AAIDD was founded in 1876, making it the oldest inter-disciplinary professional society with a focus on intellectual disability in the world. Since its inception, AAIDD has produced guidelines naming, defining, and diagnosing the condition known today as “intellectual disability.”
The first official AAIDD definition and classification manual on intellectual disability was published in 1910 (Committee on Classification of the Feebleminded, 1910), and it was the first professional definition that proposed an international terminology and classification system for intellectual disability.
AAIDD has revised its definition and diagnostic criteria as the science and understanding of the condition has evolved over time. The 12th edition of the AAIDD manual was published in 2021 (Schalock, Luckasson, & Tassé, 2021).