There are frequent claims in the literature that a majority of children With autism are mentally retarded (MR). The present study examined the evidence used as the basis for these claims, revieWing 215 articles published betWeen 1937 and 2003. Results indicated 74% of the claims came from nonempirical sources, 53% of Which never traced back to empirical data. Most empirical evidence for the claims Was published 25 to 45 years ago and Was often obtained utilizing developmental or adaptive scales rather than measures of intelligence. Furthermore, significantly higher prevalence rates of MR Were reported When these measures Were used. Overall, the findings indicate that more empirical evidence is needed before conclusions can be made about the percentages of children With autism Who are mentally retarded.
Get full access to this article
View all access options for this article.
References
1.
American Psychiatric Association. (1980). Diagnostic and statistical manual of mental disorders (3rd ed.). Washington, DC: Author .
2.
American Psychiatric Association. (1987). Diagnostic and statistical manual of mental disorders (3rd ed., rev.). Washington, DC: Author.
3.
American Psychiatric Association. (1994). Diagnostic and statistical manual of mental disorders (4th ed.). Washington, DC: Author .
4.
American Psychiatric Association. (2000). Diagnostic and statistical manual of mental disorders (4th ed., text rev.). Washington, DC: Author.
5.
Arvidsson, T., Danielsson, B., Forsberg, P., Gillberg, C., Johansson, M., & Kjellgren, G. (1997). Autism in 3—6 year old children in a suburb of Göteborg, Sweden. Autism, 1, 163—173.
6.
Asarnow, R.F., Tanguay, P.E., Bott, L., & Freeman, B.J. (1987). Patterns of intellectual functioning in non-retarded autistic and schizophrenic children. Journal of Child Psychology and Psychiatry, and Allied Disciplines, 28, 273—280.
7.
Bayley, N. (1969). Manual: Bayley Scales of Infant Development. New York: Psychological Corp.
8.
Bettleheim, B. (1967). The empty fortress: Infantile autism and the birth of the self. New York: The Free Press.
9.
Bodfish, J.W., Symons, F.J., Parker, D.E., & Lewis, M.H. (2000). Varieties of repetitive behavior in autism: Comparison to mental retardation. Journal of Autism and Developmental Disorders, 30, 237—243.
10.
Brown, J.L. (1978). Long-term follow-up of 100 “atypical” children of normal intelligence. In M. Rutter & E. Schopler (Eds.), Autism (pp. 463—474). New York: Plenum Press.
11.
Burack, J.A. (1992). Debate and argument: Clarifying developmental issues in the study of autism. Journal of Child Psychology and Psychiatry and Allied Disciplines, 33, 617—621.
12.
Burack, J.A. (1994). Selective attention deficits in persons with autism: Preliminary evidence of an inefficient attentional lens. Journal of Abnormal Psychology, 103, 535—543.
13.
Burack, J.A., Enns, J.T., Stauder, J.E.A., Mottron, L., & Randolph, B. (1997). Attention and autism: Behavioral and electrophysiological evidence. In D. J. Cohen & F. R. Volkmar (Eds.), Handbook of autism and pervasive developmental disorders (2nd ed., pp. 226—247). New York: Wiley.
14.
Burack, J.A., & Volkmar, F.R. (1992). Development of low- and high-functioning autistic children. Journal of Child Psychology and Psychiatry and Allied Disciplines, 33, 607—616.
15.
Chakrabarti, S., & Fombonne, E. (2001). Pervasive developmental disorders in preschool children. Journal of theAmerican Medical Association, 285, 3093—3099.
16.
Creak, M. (1961). Schizophrenic syndrome in childhood. Lancet, 2, 818.
17.
Creak, E.M. (1963). Childhood psychosis: A review of 100 cases. The British Journal of Psychiatry, 109, 84—89.
Dawson, G., & Lewy, A. (1989). Arousal, attention, and the socio-emotional impairments of individuals with autism. In G. Dawson (Ed.), Autism: Nature, diagnosis, and treatment (pp. 49—74). New York: Guilford Press.
20.
deBildt, A., Sytema, S., Ketelaars, C., Kraijer, D., Volkmar, F., & Minderaa, R. (2003). Measuring pervasive developmental disorders in children and adolescents with mental retardation: A comparison of two screening instruments used in a study of the total mentally retarded population from a designated area. Journal of Autism and Developmental Disorders , 33, 595—605.
21.
DeMyer, M.K. (1979). Parents and children in autism. Washington, DC: V. H. Winston & Sons.
22.
DeMyer, M.K., Barton, S., Alpern, G.D., Kimberlin, C., Allen, J., & Steele, R. (1974). The measured intelligence of autistic children . Journal of Autism and Childhood Schizophrenia, 4, 42—60.
23.
Dennis, M., Lockyer, L., Lazenby, A.L., Donnelly, R.E., Wilkinson, M., & Schoonheyt, W. (1999). Intelligence patterns among children with high-functioning autism, phenylketonuria, and childhood head injury. Journal of Autism and Developmental Disorders, 29, 5—16.
24.
Doll, E.E. (1965). Vineland Social Maturity Scale, condensed revised edition. Manual of direction. Minneapolis, MN: American Guidance Service.
25.
Edelson, M.G., Schubert, D.T., & Edelson, S.M. (1998). Factors predicting intelligence scores on the TONI in individuals with autism. Focus on Autism and Other Developmental Disabilities, 13, 17—26.
26.
Erickson, M.T. (1998). Behavior disorders of children and adolescents: Assessment, etiology and intervention. Upper Saddle River, NJ: Prentice Hall.
27.
Fogelman, C.J. (1975). American Association on Mental Deficiency (AAMD) Adaptive Behavior Scale, revision. Washington, DC: AAMD.
28.
Fombonne, E., & du Mazaubrun, C. (1992). Prevalence of infantile autism in four French regions. Social Psychiatry and Psychiatric Epidemiology, 27, 203—210.
29.
Fombonne, E., du Mazaubrun, C., Cans, C., & Grandjean, H. (1997). Autism and associated medical disorders in a French epidemiological survey. Journal of the American Academy of Child and Adolescent Psychiatry, 36, 1561—1569.
30.
Fombonne, E., Siddons, F., Achard, S., Frith, U., & Happé, F. (1994). Adaptive behavior and theory of mind in autism . European Child & Adolescent Psychiatry, 3, 176—186.
31.
Freeman, B.J., & Ritvo, E.R. (1976). Cognitive assessment. In E. R. Ritvo, B. J. Freeman, E. M. Ornitz, & P. E. Tanguay (Eds.), Autism: Diagnosis, current research, and management (pp. 27—39). New York: Spectrum.
32.
Gibson, D. (1968). Early infantile autism: Symptom and syndrome. Canadian Psychology, 9, 36—39.
33.
Gillberg, C. (1993). Autism and related behaviours. Journal of Intellectual Disability Research, 37, 343—372.
34.
Gillberg, C., & Coleman, M. (2000). The biology of the autistic syndromes. London: Mac Keith Press.
35.
Gillberg, C., Steffenburg, S., & Schaumann, H. (1991). Is autism more common now than 10 years ago?The British Journal of Psychiatry, 158, 403—409.
36.
Gillies, S. (1965). Some abilities of psychotic children and subnormal controls. Journal of Mental Deficiency Research, 9, 89—101.
37.
Gittelman, M., & Birch, H.G. (1967). Childhood schizophrenia: Intellect, neurologic status, perinatal risk, prognosis, and family pathology. Archives of General Psychiatry,17, 16—25.
38.
Goldman, J., L'Engle Stein, C., & Guerry, S. (1983). Psychological methods of child assessment. New York: Bruner/Mazel.
39.
Happé, F. (1999). Autism: Cognitive deficit or cognitive style? Trends in Cognitive Sciences, 3, 216—222.
40.
Honda, H., Shimizu, Y., Misumi, K., Niimi, M., & Ohashi, Y. (1996). Cumulative incidence and prevalence of childhood autism in children in Japan. The British Journal of Psychiatry , 169, 228— 235.
41.
Kanner, L. (1943). Autistic disturbances of affective contact. Nervous, 2, 217—250.
42.
Kasari, C., Freeman, S.F.N., & Paparella, T. (2001). Early intervention in autism: Joint attention and symbolic play. In L. M. Glidden (Ed.), International review of research in mental retardation: Vol. 23. Autism (pp. 207—237). San Diego: Academic Press.
43.
Koegel, L.K., Koegel, R.L., & Smith, A. (1997). Variables related to differences in standardized test outcomes for children with autism. Journal of Autism and Developmental Disorders, 27, 233— 244.
44.
Kolvin, I., Humphrey, M., & McNay, A. (1971). VI. Cognitive factors in childhood psychoses. The British Journal of Psychiatry, 118, 415—419.
45.
Lewis, V. (2003). Disorders of development. In A. Slater & G. Bremner (Eds.), An introduction to developmental psychology (pp. 456— 475). Malden, MA: Blackwell.
46.
Liss, M., Harel, B., Fein, D., Allen, D., Dunn, M., Feinstein, C., et al. (2001). Predictors and correlates of adaptive functioning in children with developmental disorders. Journal of Autism and Developmental Disorders, 31, 219—230.
47.
Lockyer, L., & Rutter, M. (1970). A five- to fifteen-year follow-up study of infantile psychosis: IV. Patterns of cognitive ability. The British Journal of Social and Clinical Psychology, 9, 152—163.
48.
Lord, C., & Paul, R. (1997). Language and communication in autism. In D. J. Cohen & F. R. Volkmar (Eds.), Handbook of autism and pervasive developmental disorders (2nd ed., pp. 195—225). New York: Wiley.
49.
Lotter, V. (1966a). Epidemiology of autistic conditions in young children: I. Prevalence. Social Psychiatry. Sozialpsychiatrie. Psychiatrie Sociale, 1, 124—137.
50.
Lotter, V. (1966b). Services for a group of autistic children in Middlesex. In L. Wing (Ed.), Early childhood autism: Clinical, educational and social aspects (pp. 241—255). Oxford: Pergamon Press.
51.
Magnússon, P., & Sæmundsen, E. (2001). Prevalence of autism in Iceland. Journal of Autism and Developmental Disorders, 31, 153— 163.
Minshew, N.J., Johnson, C., & Luna, B. (2001). The cognitive and neural basis of autism: A disorder of complex information processing and dysfunction of neocortical systems. In L. M. Glidden (Ed.), International review of research in mental retardation: Vol. 23. Autism (pp. 111—138). San Diego: Academic Press.
54.
Mittler, P. (1966). The psychological assessment of autistic children . In L. Wing (Ed.), Early childhood autism: Clinical, educational and social aspects (pp. 145—158). Oxford: Pergamon Press.
55.
Myers, B.A. (1989). Misleading cues in the diagnosis of mental retardation and infantile autism in the preschool child. Mental Retardation , 27, 85—90.
56.
Piotrowski, Z.A. (1937). A comparison of congenitally defective children with schizophrenic children in regard to personality structure and intelligence type. Proceedings of the American Association on Mental Deficiency , 42, 78—90.
57.
Pollack, M. (1958). Brain damage, mental retardation, and childhood schizophrenia. The American Journal of Psychiatry,115, 422— 428.
58.
Prior, M., & Ozonoff, S. (1998). Psychological factors in autism. In F. R. Volkmar (Ed.), Autism and pervasive developmental disorders (pp. 64—108). Cambridge: Cambridge University Press.
59.
Prior, M., & Werry, J.S. (1986). Autism, schizophrenia, and allied disorders. In H. C. Quay & J. S. Werry (Eds.), Psychopathological disorders of childhood (pp. 156—210). New York: Wiley .
60.
Ritvo, E.R., & Freeman, B.J. (1978). Current research on the syndrome of autism. Journal of the American Academy of Child Psychiatry, 17, 565—575.
61.
Rogers, S.J. (2001). Diagnosis of autism before the age of 3. In L. M. Glidden (Ed.), International review of research in mental retardation: Vol. 23. Autism (pp. 1—31). San Diego: Academic Press.
62.
Ruble, L.A., & Dalrymple, N.J. (2003). Social/sexual awareness of persons with autism: A parental perspective. Archives of Sexual Behavior, 22, 229—240.
63.
Rutter, M. (1966a). Behavioural and cognitive characteristics of a series of psychotic children. In L. Wing (Ed.), Early childhood autism: Clinical, educational and social aspects (pp. 51—81). Oxford: Pergamon Press.
64.
Rutter, M. (1966b). Prognosis: Psychotic children in adolescence and early adult life. In L. Wing (Ed.), Early childhood autism: Clinical, educational and social aspects (pp. 83—99). Oxford: Pergamon Press.
65.
Rutter, M. (1978). Language disorder and infantile autism. In M. Rutter & E. Schopler (Eds.), Autism (pp. 85—104). New York: Plenum Press.
66.
Rutter, M. (1974). The development of infantile autism. Psychological Medicine, 4, 147—163.
67.
Rutter, M. (1999). The Emanuel Miller Memorial Lecture 1998: Autism: Two-way interplay between research and clinical work. Journal of Child Psychology and Psychiatry and Allied Disciplines, 40, 169—188.
68.
Rutter, M., Bartak, L., & Newman, S. (1971). Autism—A central disorder of cognition and language? In M. Rutter (Ed.), Infantile autism: Concepts, characteristics, and treatment (pp. 148—171). Edinburgh: Churchill Livingstone.
69.
Rutter, M., & Lockyer, L. (1967). A five- to fifteen-year follow-up study of infantile psychosis. I. Description of sample. The British Journal of Psychiatry, 113, 1169—1182.
70.
Schreibman, L. (1988). Autism. Newbury Park, CA: Sage.
Shah, A., & Holmes, N. (1985). Brief report: The use of the Leiter International Performance Scale with autistic children. Journal of Autism and Developmental Disorders, 15, 195—203.
73.
Sigman, M., Dissanayake, C., Arbelle, S., & Ruskin, E. (1997). Cognition and emotion in children and adolescents with autism. In D. J. Cohen & F. R. Volkmar (Eds.), Handbook of autism and pervasive developmental disorders (2nd ed., pp. 248—265). New York: Wiley .
74.
Sponheim, E., & Skjeldal, O. (1998). Autism and related disorders: Epidemiological findings in a Norwegian study using ICD-10 diagnostic criteria. Journal of Autism and Developmental Disorders, 28, 217—227.
75.
Tager-Flusberg, H. (1989). A psycholinguistic perspective on language development in the autistic child. In G. Dawson (Ed.), Autism: Nature, diagnosis, and treatment (pp. 92—115). New York: Guilford Press.
Turner, S.M., DeMers, S.T., Roberts Fox, H., & Reed, G.M. (2001). APA's guidelines for test user qualifications: An executive summary. The American Psychologist, 56, 1099—1113.
78.
Viitamaki, R.O. (1964). II. Psychoses in childhood: A psychological follow-up study. Acta Psychiatrica Scandinavica, 40(Suppl. 174), 35—73.
79.
Volkmar, F.R. (2003). Ask the editor. Journal of Autism and Developmental Disorders, 33, 109—110.
80.
Volkmar, F.R., & Cohen, D.J. (1988). Classification and diagnosis of childhood autism . In E. Schopler & G. B. Mesibov (Eds.), Diagnosis and assessment in autism (pp. 71—89). New York: Plenum Press.
81.
Volkmar, F.R., & Klin, A. (2001). Asperger's disorder and higher functioning autism: Same or different? In L. M. Glidden (Ed.), International review of research in mental retardation: Vol. 23. Autism (pp. 83—110). San Diego: Academic Press.
82.
Vorster, D. (1960). An investigation into the part played by organic factors in childhood schizophrenia. Journal of Mental Science , 106, 494—522.
83.
Wechsler, D. (1991). Manual for the Wechsler Intelligence Scale for Children —Third edition. New York: Psychological Corp.
84.
Wicks-Nelson, R., & Israel, A.C. (2000). Behavior disorders of childhood. Upper Saddle River, NJ: Prentice Hall.
85.
Wignyosumarto, S., Mukhlas, M., & Shirataki, S. (1992). Epidemiological and clinical study of autistic children in Yogyakarta, Indonesia. The KobeJournal of Medical Sciences, 38, 1—19.
86.
Wing, L. (1969). The handicaps of autistic children—A comparative study. Journal of Child Psychology and Psychiatry, and Allied Disciplines, 10, 1—40.
87.
Wing, L. (1974). Language development and autistic behavior in severely mentally retarded children. Proceedings of the Royal Society of Medicine, 67, 1031—1032.
88.
Wing, L. (1976). Epidemiology and theories of aetiology. In L. Wing (Ed.), Early childhood autism (pp. 65—92). Oxford: Pergamon Press.
89.
Zelazo, P.D., Burack, J.A., Boseovski, J.J., Jacques, S., & Frye, D. (2001). A cognitive complexity and control framework for the study of autism. In J. A. Burack, T. Charman, N. Yirmiya, & P. R. Zelazo (Eds.), The development of autism: Perspectives from theory and research (pp. 195—217). Mahwah, NJ: Erlbaum.
