The Renaming of Mental Retardation : Understanding the Change to the Term Intellectual Disability

There is considerable and intense discussion in the field of intellectual disability/mental retardation about the construct of disability, how intellectual disability fits within the general construct of disability, and the use of the term intellectual disability (Glidden, 2006; Greenspan, 2006; MacMillan, Siperstein, Schalock Switzky Schroeder, Gertz, (b) the blurring of the historical distinction between biological and social causes of disability (Institute of Medicine, 1991) ; and (c) the recognition of the multidimensionality of human functioning (Luckasson et al. , 1992, 2002; World Health Organization WHO, 2001). Because of these factors, the concept of disability has evolved from a person-centered trait or characteristic (often referred to as a “deficit”) to a human phenomenon with its genesis in organic and/or social factors. These organic and social factors give rise to functional limitations that reflect an inability or constraint in both personal functioning and performing roles and tasks expected of an individual within a social environment (De Ploy Hahn Nagi, 1991; Oliver, 1996; Rioux, 1997). This social–ecological conception of disability is reflected well in current publications of both the American Association on Mental Retardation (AAMR), now the AAIDD, and WHO. In the 2002 Manual (Luckasson et al. , 2002), disability was defined as the expression of limitations in individual functioning within a social context and represents a substantial disadvantage to the individual. Similarly, in the World Health Organization's (2001) International Classification of Functioning, disability is described as having its genesis in a health condition (disorder or disease) that gives rise to impairments in body functions and structures, activity limitations, and participation restrictions within the context of personal and environmental factors. The importance of this evolutionary change in the construct of disability is that intellectual disability is no longer considered entirely an absolute, invariate trait of the person (DeKraai, 2002; Devlieger, Rusch, Greenspan, 1999). Rather, this social–ecological construct of disability, and intellectual disability, (a) exemplifies the interaction between the person and their environment; (b) focuses on the role that individualized supports can play in enhancing individual functioning; and (c) allows for the pursuit and understanding of “disability identity, ” whose principles include self-worth, subjective well-being, pride, common cause, policy alternatives, and engagement in political action (Powers, Dinerstein, Putnam, 2005; Schalock, 2004; Vehmas, 2004). The term intellectual disability is increasingly being used instead of mental retardation. Terminology for what is now referred to as intellectual disability has varied historically. Over the last 200 years, terms have included idiocy, feeblemindedness, mental deficiency, mental disability, mental handicap, and mental subnormality (Goodey, 2005; Mercer, 1992; Schroeder et al. , 2002; Stainton, 2001; Trent, 1994; Wright Hayden Rapley, 2004; Snell (b) subjected to something or not subjected to it (e. g. , involuntary commitment) ; (c) exempted from something or not exempted (e. g. , from the death penalty) ; (d) included or not included (as to protections against discrimination and equal opportunity) ; and/or (e) entitled or not entitled (e. g. , as to Social Security benefits). Historically, four broad approaches (i. e. , social, clinical, intellectual, and dual-criterion) have been used for purposes of definition and classification. Remnants of these four approaches are still evident in current discussions regarding who is (or should be) diagnosed as an individual with an intellectual disability (see, for example, Switzky Goodey, 2006; Greenspan, 2006). With the rise of the medical model, the definitional focus shifted to one's symptom complex and clinical syndrome. This approach did not negate the social criterion but gradually shifted towards a more medical model that included an increase in the relative role of organicity, heredity, and pathology and led to a call for segregation (Devlieger et al. , 2003). With the emergence of intelligence as a viable construct and the rise of the mental testing movement, the approach changed to an emphasis on intellectual functioning as measured by an intelligence test and reflected in an IQ score. This emphasis led to the emergence of IQ-based statistical norms as a way to both define the group and classify individuals within it (Devlieger, 2003). The first formal attempt to systematically use both intellectual functioning and adaptive behavior to define the class was found in the 1959 American Association on Mental Deficiency (AAMD) Manual (Heber, 1959), in which mental retardation was defined as referring to subaverage general intellectual functioning that originates during the developmental period and is associated with impairments in maturation, learning, and social adjustment. In the 1961 AAMD Manual (Heber, 1961), maturation, learning, and social adjustment were folded into a single, largely undefined new term, adaptive behavior, that has been used in all subsequent AAMR manuals. The dual-criterion approach also has included age of onset as an accompanying element. Although the term or name has changed over time, an analysis of the definitions used over the last 50+ years shows that the three essential elements of intellectual disability/mental retardation— limitations in intellectual functioning, behavioral limitations in adapting to environmental demands, and early age of onset—have not changed substantially. A summary of this analysis is presented in Appendix A (definition) and Appendix B (age of onset criterion). Consistency is also reflected in related concepts and definitions not shown in Appendices A and B. For example, Scheerenberger (1983) reported that the major elements (intellectual deficits, problems coping with the demands of everyday life, and onset during the developmental period) common to the current definition were used by professionals in the United States as early as 1900. Similarly, the National Research Council (2002, pp. 1–5) reported that the first formal AAMR/AAIDD definition of the phenomenon was in 1910. This definition defined such persons as being feebleminded, with development arrested at an early age or as evidenced by an inability to manage the demands of daily life or keep up with peers. Analogously, the Individuals With Disabilities Education Act of 2004 defines mental retardation as significantly subaverage general intellectual functioning, existing concurrently with deficits in adaptive behavior, and manifesting during the developmental period that adversely affects a child's educational performance. Appendix C summarizes how the establishment of boundaries has been operationalized in the AAMR/AAIDD manuals since 1959. Two essential points are evident in these operationalizations. First, the cut-off criterion, based on SDs from a population mean, pertained primarily to the IQ element. As of the 2002 AAMR Manual, a corresponding cut-off criterion was established for the adaptive behavior element. Second, SDs currently are and primarily have been used to establish the boundary of intellectual disability. The three appendices show clearly how both the definition and its operationalization have remained consistent over time. The minor changes that have occurred reflect three phenomena: (a) advances in understanding of intellectual functioning and adaptive behavior; (b) advances in measurement theory and strategies that permit the use of statistical procedures to control for measurement error (standard error of measurement), practice effects, and normative changes over time; and (c) the essential role of clinical judgment in the administration, scoring, and interpretation of psychometric instruments (Schalock Schalock et al. , 2007). This historical consistency supports the trend in the field and the conclusion of the major organizations that regardless of the term used to name this disability, the same population has been described. This conclusion is the same as that drawn by The President's Committee for People With Intellectual Disabilities (2004), which stated, This conclusion is critical because of the essential role that the term mental retardation plays in public policy. For example, in the United States, a diagnosis of mental retardation is commonly used to determine eligibility under state and federal disability programs, such as Individuals With Disabilities Education Act—IDEA (2004), Social Security Disability Insurance, and Medicaid Home and Community Based Waiver. In addition, the term mental retardation is also used for citizenship and legal status, civil and criminal justice, early care and education, training and employment, income support, health care, and housing and zoning (Schroeder et al. , 2002). Intellectual disability is the currently preferred term for the disability historically referred to as mental retardation, and the authoritative definition and assumptions promulgated by the AAIDD (previously the AAMR) remain the same. The term intellectual disability covers the same population of individuals who were diagnosed previously with mental retardation in number, kind, level, type, and duration of the disability, and the need of people with this disability for individualized services and supports. Furthermore, every individual who is or was eligible for a diagnosis of mental retardation is eligible for a diagnosis of intellectual disability. The fact that the construct of intellectual disability belongs within the general construct of disability helps one understand why the term intellectual disability has emerged as a preferred term to replace mental retardation. The term intellectual disability (a) reflects the changed construct of disability proposed by AAIDD and WHO; (b) aligns better with current professional practices that are focused on functional behaviors and contextual factors; (c) provides a logical basis for individualized supports provision due to its basis in a social–ecological framework; (d) is less offensive to persons with disabilities; and (e) is more consistent with international terminology. We anticipate that discussions will continue in an attempt to further refine the construct of intellectual disability, improve the reliability of diagnosis, and better understand these aspects of human functioning: the nature of intelligence, adaptive behavior, and disablement. In addition, the field will continue to examine the relationships between people with intellectual disability and other defined groups (such as those with learning disability, developmental disability, and traumatic brain injury) ; the provision of individualized supports to enhance individual functioning; the impact of the consumer and reform movements on the field; the effects of terminology upon peoples' lives; and the impact of an increased understanding of the biomedical, genetic, and behavioral aspects of the condition (Luckasson, 2003; Schalock Switzky the term, however, is changed to intellectual disability. 1959 (Heber): Mental retardation refers to subaverage general intellectual functioning which originates during the developmental period and is associated with impairment in one or more of the following: (1) maturation, (2) learning, (3) social adjustment. (p. 3) 1961 (Heber): Mental retardation refers to subaverage general intellectual functioning which originates during the developmental period and is associated with impairment in adaptive behavior. (p. 3) 1973 (Grossman): Mental retardation refers to significantly subaverage general intellectual functioning existing concurrently with deficits in adaptive behavior, and manifested during the developmental period. (p. 1) 1983 (Grossman): Same as 1973. (p. 1) 1992 (Luckasson et al. ): Mental retardation refers to substantial limitations in present functioning. It is characterized by significantly subaverage intellectual functioning, existing concurrently with related limitations in two or more of the following applicable adaptive skill areas: communication, self-care, home living, social skills, community use, self-direction, health and safety, functional academics, leisure, and work. Mental retardation manifests before age 18. (p. 1) 2002 (Luckasson et al. ): Mental retardation is a disability characterized by significant limitations both in intellectual functioning and in adaptive behavior as expressed in conceptual, social, and practical adaptive skills. This disability originates before age 18. (p. 1) 1968 (DSM–II): Mental retardation refers to subnormal general intellectual functioning which originates during the developmental period and is associated with impairment of either learning and social adjustment or maturation, or both. (These disorders were classified under “chronic brain syndrome with mental deficiency” and “mental deficiency” in DSM–I. ) (p. 14) 1980 (DSM–III): The essential features are: (1) significantly subaverage general intellectual functioning, (2) resulting in, or associated with, deficits or impairments in adaptive behavior, (3) with onset before the age of 18. (p. 36) 1987 (DSM–III–R): The essential features of this disorder are: (1) significantly subaverage general intellectual functioning, accompanied by (2) significant deficits or impairments in adaptive functioning, with (3) onset before age of 18. (p. 28) 1994 (DSM–IV): The essential feature of mental retardation is significantly subaverage general intellectual functioning (Criterion A) that is accompanied by significant limitations in adaptive functioning in at least two of the following skill areas: communication, self-care, home living, social/interpersonal skills, use of community resources, self-direction, functional academic skills, work, leisure, health, and safety (Criterion B). The onset must occur before age 18 years (Criterion C). Mental retardation has many different etiologies and may be seen as a final common pathway of various pathological processes that affect the functioning of the central (p. Same as (p. A state of mental from or from an early due to (p. A state of mental (p. A state of social at or to at resulting from developmental of (p. which originates during the developmental period (i. e. , (p. manifested during the developmental period age at 18 (p. manifested during the developmental period of time between conception and the (p. et Mental retardation manifests before age 18. et This disability originates before age 18. (p. (Heber): one the population of the age group on of general intellectual functioning. (p. 3) 1961 (Heber): one the population (p. 3) 1973 (Grossman): Two or more SDs the population (p. (Grossman): IQ of or on of is as a and be to or (p. (Luckasson et al. ): IQ of to or based on that one or more general intelligence (p. (Luckasson et al. ): two SDs the mean, the error of measurement for the instruments used and the and (p. (Luckasson et al. ): that is at least two SDs the of either (a) one of the following three of adaptive conceptual, social, or or (b) an on a of conceptual, social, and practical skills. (p.