Intellectual Disabilities and Global Developmental Delay

Abstract

The diagnosis of intellectual disability (ID)/intellectual developmental disorder (IDD) and global developmental delay has evolved over time to the current definition that extends well beyond the original concepts, which were largely based on a statistical conceptualization of a general subaverage intellectual functioning, as measured by the intelligence quotient (IQ). The Diagnostic and Statistical Manual of Mental Disorders, 5th ed. (DSM-5; APA, 2013a) attempts to broaden the category of intellectual disability/IDD and approach it in more clinical terms. Diagnostic criteria presently utilize the need for an assessment of both cognitive capacity (IQ) and adaptive functioning. The essential features of intellectual disability (intellectual developmental disorder) are (A) deficits in general intellectual abilities; (B) impairment in everyday adaptive functioning, in comparison to an individual's age-, gender-, and socioculturally matched peers; and (C) onset that is during the developmental period. This chapter provides an overview of the history of intellectual disability and global developmental delay in the DSMs. It discusses the etiology, prevalence, symptom presentation, course and developmental challenges, evaluation and treatment. (PsycInfo Database Record (c) 2023 APA, all rights reserved)