A systematic review of the diagnostic stability of Autism Spectrum Disorder Sue Woolfenden a,b, *, Vanessa Sarkozy a,b , Greta Ridley b , Katrina Williams c,d a University of New South Wales, Australia b Sydney Children’s Hospital Network, Australia c Royal Children’s Hospital Melbourne, Australia d University of Melbourne, Australia 1. Introduction Autism Spectrum Disorder (ASD) affects between 60 and 70/10,000 children (Fombonne, 2009). Core features of ASD are severe and pervasive deficits in social communication and interactions; and restricted, repetitive patterns of behaviour, interests, and activities (Levy, Mandell, & Schultz, 2009). Males are affected about four times more frequently than females. Although there is currently no known cause, evidence suggests that the cause is highly genetic with multifactorial risk factors that interact leading to changes in brain development (Levy et al., 2009). There are distinct diagnostic classifications within ASD in which there is the requirement for various types and numbers of criteria within the three clinical domains of communication, social interaction and behaviour problems/differences. While ‘Autism Spectrum Disorder’ is a commonly used term in clinical practice it is not recognised by current mainstream disease classification systems such as the DSM-IV and DSM-IV-TR (American Psychiatric Association, 1994, 2000), and IDC-9/10 criteria (World Health Organization, 1993, 2007). Although this has been mooted to change in the next edition of DSM, DSM Research in Autism Spectrum Disorders 6 (2012) 345–354 A R T I C L E I N F O Article history: Received 21 June 2011 Received in revised form 26 June 2011 Accepted 27 June 2011 Available online 4 August 2011 Keywords: Diagnostic stability Autism Autistic Disorder Autism Spectrum Disorder Children Prognosis A B S T R A C T There is debate in the current literature regarding the permanence of an Autism Spectrum Disorder (ASD) diagnosis. We undertook a systematic review of the diagnostic stability of ASD to summarise current evidence. A comprehensive search strategy was used to identify studies. Participants were children with ASD. Risk of bias was assessed by examining the sample selected, recruitment method, completeness of follow up, timing of diagnosis and blinding. Twenty three studies assessed diagnostic stability with a total of 1466 participants. Fifty three to100% of children still had a diagnosis of Autistic Disorder (AD) and 14–100% of children still had a diagnosis of another form of ASD at follow up. There is some evidence that Autistic Disorder is a reasonably stable diagnosis; however a significant minority of children will no longer meet diagnostic criteria after a period of follow up, particularly those diagnosed in the preschool years with cognitive impairment. Other Autism Spectrum Disorders have very variable stability between studies and clinicians when using this diagnosis need inform parents of its instability. This study supports the stricter diagnostic criteria in DSM-V. There is a need for long term, large population cohort studies measuring diagnostic stability. Crown Copyright ß 2011 Published by Elsevier Ltd. All rights reserved. * Corresponding author at: Community Paediatrician, Sydney Children’s Hospitals Network (Randwick), High St, Randwick 2031 NSW, Australia. Tel.: +61 293828183; fax: +61 293828188. E-mail addresses: susan.woolfenden@sesiahs.health.nsw.gov.au, susanmarkw@hotmail.com (S. Woolfenden). Contents lists available at ScienceDirect Research in Autism Spectrum Disorders Jo ur n al h o mep ag e: ht tp ://ees.els evier.c o m/RA SD/d efau lt.asp 1750-9467/$ – see front matter . Crown Copyright ß 2011 Published by Elsevier Ltd. All rights reserved. doi:10.1016/j.rasd.2011.06.008