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Diagnosing Autism Spectrum Disorder: Who Will Get a DSM-5 Diagnosis?

Thursday, 2 May 2013: 09:00-13:00
Banquet Hall (Kursaal Centre)
R. G. Kent1, S. J. Carrington2, A. S. Le Couteur3, J. Gould4, L. Wing5, J. P. W. Maljaars6,7, I. Noens7, I. A. van Berckelaer-Onnes6 and S. R. Leekam8, (1)Wales Autism Research Centre, Cardiff University, Cardiff, United Kingdom, (2)Wales Autism Research Centre, Cardiff, United Kingdom, (3)Institute of Health and Society, Newcastle University, Newcastle upon Tyne, United Kingdom, (4)Lorna Wing Centre, National Autistic Society, Bromley, United Kingdom, (5)National Autistic Society, Bromley, United Kingdom, (6)Leiden University, Leiden, Netherlands, (7)Parenting and Special Education Research Unit, University of Leuven (KU Leuven), Leuven, Belgium, (8)Wales Autism Research Centre, School of Psychology, Cardiff University, Cardiff, United Kingdom
Background:   Introduction of proposed criteria for DSM-5 Autism Spectrum Disorder (ASD) has led to concern that some high functioning individuals who currently meet diagnostic criteria for Pervasive Developmental Disorder (DSM-IV-TR/ICD-10) will not qualify for a diagnosis under the proposed changes.

Objectives: The aim of the study was to investigate who would meet criteria for a draft DSM-5 diagnosis in data that was not collected specifically for the purpose of diagnosis according to DSM-IV-TR or ICD-10.  

Methods:   To investigate this, a new DSM-5 ASD algorithm was designed and tested using the Diagnostic Interview for Social and Communication Disorders (DISCO). First, sensitivity and specificity was tested using a clinically-matched sample [N=82] and further tested using an independent dataset [N=115]. Second, the output of the DISCO DSM-5 algorithm was compared with that of the DISCO ICD-10 algorithm using a dataset of individuals ranging in ability and age (N=200). This included a subset with Gillberg’s Asperger Syndrome (Gillberg et al., 2001) and a subset with ICD-10 Atypical Autism. Finally, modifications were made to the DSM-5 algorithm to improve sensitivity.

Results:   Sensitivity and specificity was good for identification of cases with clinical autism (AUC <.87-.89 for the validation sample). Convergence was high between DISCO outputs for DSM-5 ASD and ICD-10 Childhood Autism (96%) and between DSM-5 ASD and Gillberg’s Asperger Syndrome (90%). No age or gender effects were found. Across all samples, 13%, mostly high functioning, did not meet DSM-5 criteria. Removing the age of onset criterion increased sensitivity without reducing specificity. Adjusting the social communication criterion increased sensitivity but with loss of specificity.

Conclusions:   Use of the DISCO DSM-5 algorithm indicates that the proposed DSM-5 changes should identify the majority of individuals who currently receive a diagnosis of ICD-10 Childhood Autism or Gillberg’s Asperger Syndrome.

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