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Psychological Markers in the Detection of Autism in Infancy in a Large Population

  • Simon Baron-Cohen (a1), Antony Cox (a2), Gillian Baird (a2), John Swettenham (a3), Natasha Nightingale (a4), Kate Morgan (a4), Auriol Drew (a4) and Tony Charman (a5)...

Investigation to see if there are key psychological risk indicators for autism in a random population study of children at 18 months of age; and to assess how well these discriminate children who receive a diagnosis of autism from other forms of developmental delay.


Sixteen thousand children in the southeast of England were screened for autism by their health visitor or GP, during their routine 18-month-old developmental check-up, using the CHAT (Checklist for Autism in Toddlers). From a previous high-risk study we predicted that children at 18 months of age who failed three items (‘protodeclarative pointing‘, ‘gaze-monitoring‘, and ‘pretend play’) would be at risk for receiving a diagnosis of autism. From other evidence, we further predicted that those 18-month-olds who failed one or two of the key items (either pretend play, or protodeclarative pointing and pretend play) would be at risk for developmental delay without autism.


Twelve children out of the total population of 16 000 consistently failed the three key items. Of these, 10 (83.3%) received a diagnosis of autism. Thus, the false positive rate was 16.6% (2 out of 12 cases), and even these 2 cases were not normal. When the 10 children with autism were reassessed at 3.5 years of age, their diagnosis remained the same. Thus the false positive rate among the cases diagnosed with autism was zero. In contrast, of 22 children who consistently failed either protodeclarative pointing and/or pretend play, none received a diagnosis of autism, but 15 (68.2%) received a diagnosis of language delay.


Consistent failure of the three key items from the CHAT at 18 months of age carries an 83.3% risk of autism; and this pattern of risk indicator is specific to autism when compared to other forms of developmental delay.

Corresponding author
Dr Baron-Cohen, University of Cambridge, Department of Experimental Psychology, Downing Street, Cambridge CB2 3EB
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In this latter subgroup, items Biii and Biv were omitted, since these would have been simply repeating questions A5 and A7.


The Autism diagnosis actually contains 2 subgroups: Autism (without any developmental delay), and Autism + Developmental Delay.


It should be noted however that with the judges who used the ADI–R (a parent-report measure only), criteria were slightly modified: To receive a diagnosis of autism, a child had to score above the traditional threshold on the first 2 axes (Reciprocal Social Interaction; and Communication), and score above a new threshold of 2 or more on the third axis (Repetitive Behaviour). This modification was made because many children scored above the traditional threshold on the first 2 axes, but just missed doing so on the third.

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Baron-Cohen, S. (1987) Autism and symbolic play. British Journal of Developmental Psychology, 5, 139148.
Baron-Cohen, S. (1989) Perceptual role-taking and protodeclarative pointing in autism. British Journal of Developmental Psychology, 7, 113127.
Baron-Cohen, S. (1995) Mindblindness. Boston: MIT Press.
Baron-Cohen, S., Allen, J. & Gillberg, C. (1992) Can autism be detected at 18 months? The needle, the haystack, and the CHAT. British Journal of Psychiatry, 161, 839843.
Bates, E., Benigni, L., Bretherton, I., et al (1979) Cognition and communication from 9–13 months: correlational findings. In The Emergence of Symbols: Cognition and Communication in Infancy (ed Bates, E.). New York: Academic Press.
Bretherton, I. (1984) Symbolic Play. London: Academic Press.
Bruner, J. (1983) Child's Talk. Oxford: Oxford University Press.
Fenson, L., Dale, P., Reznick, S., et al (1993) The MacArthur Communicative Development Inventories. San Diego: Singular Publishing Group.
Gillberg, C. (1990) What is autism? International Review of Psychiatry, 2, 6166.
Griffiths, R. (1986) The Abilities of Babies. London: University of London Press.
Kanner, L. (1943) Autistic disturbance of affective contact Nervous Child, 2, 217250. Reprinted in Kanner, L. (1973) Childhood Psychosis: Initial Studies and New Insights. New York: John Wiley and Sons.
Leslie, A. M. (1987) Pretence and representation: the origins of “theory of mind”. Psychological Review, 94, 412426.
Lord, C., Rutter, M. & Le Couteur, A. (1994) Autism Diagnostic Interview–Revised. Journal of Autism and Developmental Disorders, 24, 659686.
Scaife, M. & Bruner, J. (1975) The capacity for joint visual attention in the infant. Nature, 253, 265266.
Tomasello, M. (1988) The role of joint-attentional processes in early language acquisition. Language Sciences, 10, 6988.
Wing, L. (1976) Autistic Children. Oxford: Pergamon Press.
Wing, L., Gould, J., Yeates, S. R., et al (1977) Symbolic play in severely mentally retarded and in autistic children. Journal of Child Psychology and Psychiatry, 18, 167178.
Wing, L. & Gould, J. (1979) Severe impairments of social interaction and associated abnormalities in children: epidemiology and classification. Journal of Autism and Developmental Disorders, 9, 1129.
World Health Organization (1992) The Tenth Revision of the International Classification of Diseases and Related Health Problems (ICD–10). Geneva: WHO.
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The British Journal of Psychiatry
  • ISSN: 0007-1250
  • EISSN: 1472-1465
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Psychological Markers in the Detection of Autism in Infancy in a Large Population

  • Simon Baron-Cohen (a1), Antony Cox (a2), Gillian Baird (a2), John Swettenham (a3), Natasha Nightingale (a4), Kate Morgan (a4), Auriol Drew (a4) and Tony Charman (a5)...
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