In the Diagnostic and Statistical Manual of Mental Disorders, 4th edition (DSM-IV), autistic characteristics in social interaction and communication are described as qualitative impairments. However, the difference between autistics and nonautistics in the draft of the 5th edition (DSM-5 draft) is quantitative rather than qualitative. The word “qualitative” is deleted in the draft text, and it is specified that the relation between social demands and individual limited capacities is critical for symptom manifestation (criterion C). Because the proposed levels of support requirement in the draft are mere observable outcomes of social vulnerability, the boundary between level 1 and nonautistic condition is determined by the relation between social demands and individual capacities. In addition to the introduction of the single category (autism spectrum disorder (ASD)) to cover the entire case spectrum, the DSM-5 draft is clearly based on a conviction that ASD is indistinguishable from the normal behavioral range. This concise review provides an explanation for this implicit paradigm shift from qualitative to quantitative. Importantly, the conditional role of social demands for symptom manifestation in the draft can be plausibly interpreted using a unique liability-probability model. 1. Introduction The development process of the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) is nearing its conclusion, and it is already scheduled for release in May 2013 (http://www.dsm5.org/). Although there has been a lot of debate on the new draft criteria for autism spectrum disorder (ASD) [1–3], the official commentaries from the DSM-5 workgroup on neurodevelopmental disorders suggest minor additional revisions in the upcoming final version [4]. Because the proposals in the draft are supported by more than a decade of scientific evidences after the launch of DSM-IV, the implications in the draft proposals are significant, and it is quite meaningful to designate the implicit differences between the draft and the former version. In DSM-IV, autistic characteristics in social interaction and communication are described as qualitative impairments. However, the difference between autistics and nonautistics in the DSM-5 draft is quantitative rather than qualitative. The word “qualitative” is deleted in the draft text, and it is suggested that the diagnosis of ASD may not be confirmed until social demands exceed limited capacities as documented in the criterion C. The proposed levels of support requirement in the draft are mere observable
References
[1]
L. Wing, J. Gould, and C. Gillberg, “Autism spectrum disorders in the DSM-V: better or worse than the DSM-IV?” Research in Developmental Disabilities, vol. 32, no. 2, pp. 768–773, 2011.
[2]
A. Taheri and A. Perry, “Exploring the proposed DSM-5 criteria in a clinical sample,” Journal of Autism and Developmental Disorders, vol. 42, no. 9, pp. 1810–1817, 2012.
[3]
J. C. McPartland, B. Reichow, and F. R. Volkmar, “Sensitivity and specificity of proposed DSM-5 diagnostic criteria for autism spectrum disorder,” Journal of the American Academy of Child & Adolescent Psychiatry, vol. 51, no. 4, pp. 368–383, 2012.
[4]
S. E. Swedo, G. Baird, E. H. Cook Jr., et al., “Commentary from the DSM-5 workgroup on neurodevelopmental disorders,” Journal of the American Academy of Child & Adolescent Psychiatry, vol. 51, no. 4, pp. 347–349, 2012.
[5]
L. Wing, “The autistic spectrum,” The Lancet, vol. 350, no. 9093, pp. 1761–1766, 1997.
[6]
C. M. Freitag, “The genetics of autistic disorders and its clinical relevance: a review of the literature,” Molecular Psychiatry, vol. 12, no. 1, pp. 2–22, 2007.
[7]
C. Betancur, “Etiological heterogeneity in autism spectrum disorders: more than 100 genetic and genomic disorders and still counting,” Brain Research, vol. 1380, pp. 42–77, 2011.
[8]
S. Ijichi, N. Ijichi, Y. Ijichi, H. Sameshima, and H. Morioka, “The genetic basis of phenotypic diversity: autism as an extreme tail of a complex dimensional trait,” in Autism Spectrum Disorders: The Role of Genetics in Diagnosis and Treatment, S. I. Deutsch and M. R. Urbano, Eds., pp. 83–102, InTech, Rijeka, Croatia, 2011.
[9]
M. C. Keller and G. Miller, “Resolving the paradox of common, harmful, heritable mental disorders: which evolutionary genetic models work best?” Behavioral and Brain Sciences, vol. 29, no. 4, pp. 405–452, 2006.
[10]
D. A. Regier, “Dimensional approaches to psychiatric classification: refining the research agenda for DSM-V: an introduction,” International Journal of Methods in Psychiatric Research, vol. 16, supplement 1, pp. S1–S5, 2007.
[11]
L. Waterhouse, L. Wing, R. Spitzer, and B. Siegel, “Pervasive developmental disorders: from DSM-III to DSM-III-R,” Journal of Autism and Developmental Disorders, vol. 22, no. 4, pp. 525–549, 1992.
[12]
D. Simpson, “Autism spectrum disorder is not as certain as implied,” British Medical Journal, vol. 326, no. 7396, p. 986, 2003.
[13]
I. Kamp-Becker, J. Smidt, M. Ghahreman, M. Heinzel-Gutenbrunner, K. Becker, and H. Remschmidt, “Categorical and dimensional structure of autism spectrum disorders: the nosologic validity of asperger syndrome,” Journal of Autism and Developmental Disorders, vol. 40, no. 8, pp. 921–929, 2010.
[14]
C. Lord, E. Petkova, V. Hus, et al., “A multisite study of the clinical diagnosis of different autism spectrum disorders,” Archives of General Psychiatry, vol. 69, no. 3, pp. 306–313, 2012.
[15]
T. W. Frazier, E. A. Youngstrom, L. Speer, et al., “Validation of proposed DSM-5 criteria for autism spectrum disorder,” Journal of the American Academy of Child & Adolescent Psychiatry, vol. 51, no. 1, pp. 28.e3–40.e3, 2012.
[16]
M. Huerta, S. L. Bishop, A. Duncan, V. Hus, and C. Lord, “Application of DSM-5 criteria for autism spectrum disorder to three samples of children with DSM-IV diagnoses of pervasive developmental disorders,” American Journal of Psychiatry, vol. 169, no. 10, pp. 1056–1064, 2012.
[17]
S. Ijichi and N. Ijichi, “Computerized lifelong mentoring support using robot for autistic individuals,” Medical Hypotheses, vol. 68, no. 3, pp. 493–498, 2007.
[18]
I. Rapin, “Autims (author reply),” The New England Journal of Medicine, vol. 337, no. 21, pp. 1556–1557, 1997.
[19]
P. A. Filipek, P. J. Accardo, G. T. Baranek et al., “The screening and diagnosis of autistic spectrum disorders,” Journal of Autism and Developmental Disorders, vol. 29, no. 6, pp. 439–484, 1999.
[20]
I. Rapin, “Autism in search of a home in the brain,” Neurology, vol. 52, no. 5, pp. 902–904, 1999.
[21]
P. A. Filipek, P. J. Accardo, S. Ashwal et al., “Practice parameter: screening and diagnosis of autism. Report of the quality standards subcommittee of the American Academy of Neurology and the Child Neurology Society,” Neurology, vol. 55, no. 4, pp. 468–479, 2000.
[22]
J. N. Constantino and R. D. Todd, “Genetic structure of reciprocal social behavior,” American Journal of Psychiatry, vol. 157, no. 12, pp. 2043–2045, 2000.
[23]
D. H. Skuse, W. P. L. Mandy, and J. Scourfield, “Measuring autistic traits: heritability, reliability and validity of the Social and Communication Disorders Checklist,” British Journal of Psychiatry, vol. 187, pp. 568–572, 2005.
[24]
A. Ronald, F. Happé, and R. Plomin, “The genetic relationship between individual differences in social and nonsocial behaviours characteristic of autism,” Developmental Science, vol. 8, no. 5, pp. 444–458, 2005.
[25]
A. Ronald, F. Happé, P. Bolton et al., “Genetic heterogeneity between the three components of the autism spectrum: a twin study,” Journal of the American Academy of Child and Adolescent Psychiatry, vol. 45, no. 6, pp. 691–699, 2006.
[26]
A. Ronald, F. Happé, T. S. Price, S. Baron-Cohen, and R. Plomin, “Phenotypic and genetic overlap between autistic traits at the extremes of the general population,” Journal of the American Academy of Child and Adolescent Psychiatry, vol. 45, no. 10, pp. 1206–1214, 2006.
[27]
M. B. Posserud, A. J. Lundervold, and C. Gillberg, “Autistic features in a total population of 7-9-year-old children assessed by the ASSQ (Autism Spectrum Screening Questionnaire),” Journal of Child Psychology and Psychiatry and Allied Disciplines, vol. 47, no. 2, pp. 167–175, 2006.
[28]
R. A. Hoekstra, M. Bartels, C. J. H. Verweij, and D. I. Boomsma, “Heritability of autistic traits in the general population,” Archives of Pediatrics and Adolescent Medicine, vol. 161, no. 4, pp. 372–377, 2007.
[29]
J. N. Constantino, “The quantitative nature of autistic social impairment,” Pediatric Research, vol. 69, no. 5, pp. 55R–62R, 2011.
[30]
E. B. Robinson, K. C. Koenen, M. C. McCormick, et al., “Evidence that autistic traits show the same etiology in the general population and at the quantitative extremes (5%, 2.5%, and 1%),” Archives of General Psychiatry, vol. 68, no. 11, pp. 1113–1121, 2011.
[31]
S. Lundst？m, Z. Chang, M. R？stam, et al., “Autism spectrum disorders and autistic like traits: similar etiology in the extreme end and the normal variation,” Archives of General Psychiatry, vol. 69, no. 1, pp. 46–52, 2012.
[32]
E. B. Robinson, K. C. Koenen, M. C. McCormick, et al., “A multivariate twin study of autistic traits in 12-year-olds: testing the fractionable autism triad hypothesis,” Behavior Genetics, vol. 42, no. 2, pp. 245–255, 2012.
[33]
P. Szatmari, “New recommendations on autism spectrum disorder,” British Medical Journal, vol. 342, article d2456, 2011.
[34]
T. W. Frazier, E. A. Youngstrom, L. Sinclair et al., “Autism spectrum disorders as a qualitatively distinct category from typical behavior in a large, clinically ascertained sample,” Assessment, vol. 17, no. 3, pp. 308–320, 2010.
[35]
D. S. Falconer and T. F. C. Mackay, “Threshold characters,” in Introduction to Quantitative Genetics, D. S. Falconer and T. F. C. Mackay, Eds., pp. 299–311, Pearson, Harlow, UK, 4rth edition, 1996.
[36]
M. Al-Qabandi, J. W. Gorter, and P. Rosenbaum, “Early autism detection: are we ready for routine screening?” Pediatrics, vol. 128, no. 1, pp. e211–e217, 2011.
[37]
J. Hallmayer, S. Cleveland, A. Torres, et al., “Genetic heritability and shared environmental factors among twin pairs with autism,” Archives of General Psychiatry, vol. 68, no. 11, pp. 1095–1102, 2011.
[38]
S. Ozonoff, G. S. Young, A. Carter, et al., “Recurrence risk for autism spectrum disorders: a baby siblings research consortium study,” Pediatrics, vol. 128, no. 3, pp. e488–e495, 2011.
[39]
R. Voelker, “Autism screening strikes emotional chord,” Journal of the American Medical Association, vol. 306, no. 7, pp. 691–692, 2011.
