How Will DSM-5 Affect Autism Diagnosis? a Systematic Literature Review and Meta-Analysis

Background:  The prevalence of autism spectrum disorders has steadily increased over the past decade, leading to the emergence of autism as a major public health concern.  In May 2013, the American Psychiatric Association published the Fifth Edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) which revised DSM-IV-TR autism subgroups of autistic disorder (AD), Asperger’s Disorder, and Pervasive Developmental Disorder-Not Otherwise Specified (PDD-NOS) to combine them into one broad diagnosis—autism spectrum disorder (ASD).  The new ASD definition now includes only two main behavior categories, social communication and interaction and restrictive, repetitive behaviors. 

Objectives:  Because the new DSM-5 criteria for ASD has the potential to affect the number of children and adults who currently have or may become eligible for access to care and insurance coverage for ASD, we conducted a systematic review and meta-analysis to (1) estimate the changes in frequency of ASD diagnosis based on the proposed DSM-5 criteria; (2) determine the ASD subgroups most likely to be affected by the changes in DSM-5 criteria; and (3) present public health policy implications of implementation of DSM-5 ASD criteria.

Methods:  Using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, we searched the literature for studies that applied both DSM-IV-TR and DSM-5 autism diagnosis criteria to study samples.  Three reviewers rated the scientific rigor of each study using the Quality Appraisal of Reliability Studies (QAREL), an 11-item checklist.  Data were extracted as sample size, subjects meeting DSM-IV-TR criteria, and number no longer meeting ASD diagnostic criteria under DSM-5. Pooled effects were estimated for the proportion of subjects who no longer met criteria for ASD diagnosis and for subgroups (AD, Asperger’s Disorder, PDD-NOS) using random effects meta-analysis models. The heterogeneity of each model was assessed using Cochran Q and I²statistics. Publication bias was examined using a funnel plot.

Results:  Of 418 studies identified by the search, 14 met inclusion criteria for the systematic review and meta-analysis and 7 studies specifically examined DSM-IV-TR subgroups (AD n=7; Asperger’s Disorder n=4; PDD-NOS n=6). The most consistent area of weakness in study quality was lack of blinding with only one study reporting that raters were blinded to the results of DSM-IV-TR.  All studies consistently reported decreases in ASD diagnosis (range 7.3-68.4%) and the DSM-IV-TR subgroups of Asperger’s Disorder (16.6-100%) and PDD-NOS (50-97.5%) using DSM-5 criteria.  There were statistically significant pooled decreases in diagnoses for ASD (31% [95%CI 20.4-44.3], p=0.006) and the DSM-IV-TR subgroups of AD (22% [95%CI 16-29], p<0.001) and PDD-NOS (70% [95%CI 55-82], p=0.01); however, the pooled decrease for Asperger’s Disorder was not significant (70% [95%CI 26-94], p=0.38).  Significant heterogeneity was present in all models. There was no evidence of publication bias.

Conclusions: DSM-5 will likely decrease the number of individuals diagnosed with ASD, particularly the DSM-IV-TR PDD-NOS subgroup. Future research is needed to examine implementation of DSM-5 on diagnosis of autism and how states respond regarding insurance coverage and services for individuals without an ASD diagnosis but who still may require assistance.