Direct answer
No — OAP requires a DSM-5 ASD diagnosis. DSM-IV categories like Asperger’s Disorder, PDD-NOS, and Childhood Disintegrative Disorder were replaced in 2013 by the single Autism Spectrum Disorder umbrella. For most families, the fastest path is an updated DSM-5 letter from the original diagnosing practitioner ($200–$500), not a full re-assessment ($2,500–$4,000 private or 12–24 month public wait).
The Diagnostic and Statistical Manual of Mental Disorders (DSM) is the standard reference for psychiatric diagnosis in North America. DSM-IV (1994–2013) used separate diagnostic categories for different autism presentations. DSM-5 (2013–present) replaced all of them with a single umbrella category.
DSM-IV categories (no longer used): Autistic Disorder, Asperger’s Disorder, Pervasive Developmental Disorder — Not Otherwise Specified (PDD-NOS), Childhood Disintegrative Disorder. These categories have not been in the DSM since 2013.
DSM-5 category (current): Autism Spectrum Disorder (ASD), with severity specifiers Level 1 (requiring support), Level 2 (requiring substantial support), Level 3 (requiring very substantial support). This is what OAP requires.
ICD-11 (World Health Organization) also uses an Autism Spectrum Disorder category with equivalent criteria. Diagnoses using ICD-11 ASD are generally accepted alongside DSM-5 ASD for OAP purposes. Confirm with AccessOAP.
Asperger’s Disorder was folded into DSM-5 Autism Spectrum Disorder, but the current support level is an individual clinical judgment. Contact the original diagnosing practitioner for a review appointment and updated DSM-5 letter. Typical cost: $200–$500.
Autistic Disorder was folded into DSM-5 Autism Spectrum Disorder. An updated DSM-5 letter from the original practitioner may be feasible. Contact the original clinician first.
PDD-NOS is the most ambiguous DSM-IV category — some meet DSM-5 ASD criteria, some do not. A full new assessment is typically needed to clarify. Private cost: $2,500–$4,000. Public referral wait: 12–24 months.
Before ordering a new assessment, call AccessOAP at 1-833-425-2445. Ask whether your existing DSM-IV documentation might be sufficient. Some comprehensive assessments contain enough criteria-level detail that AccessOAP may accept them. This step costs nothing and can save thousands of dollars.
If your child was diagnosed before 2013 with a DSM-IV category, they may now be a teenager or approaching adulthood. An assessment that is 10+ years old may not reflect their current presentation — even if the underlying condition is the same.
This matters beyond OAP: a current assessment is often valuable for school accommodations, college/university disability services, and adult-services planning through Developmental Services Ontario (DSO). The cost of a current assessment is often worth it independently of the OAP requirement.
APA
American Psychiatric Association — DSM-5 Diagnostic Criteria for Autism Spectrum Disorder
AccessOAP
AccessOAP Service Coordination — registration eligibility 1-833-425-2445
Whether international autism diagnoses are accepted for Ontario OAP registration, including documentation requirements and steps when rejected.
Both diagnose autism in Ontario. General paeds: shorter wait. Developmental paeds: 12-24 months, full workup. Both OHIP-covered and accepted by AccessOAP.
Commitment to Accuracy: Our data is verified against official government reports (FAO, MCCSS), peer-reviewed scientific literature, and accessible public records. Last updated: March 24, 2026.
How many children are on the Ontario autism waitlist in 2026?
As of May 13, 2026, 91,974 children are registered with the Ontario Autism Program. However, only 20,711 (22.5%) have an active Core Funding Agreement. This represents ~300% growth in registrations since 2019, with 71,263 children still waiting for essential funding.
Source: MCCSS FOI via OAC · Mar 2026, FAO Report 2024 · Verify Link
Written by Spencer Carroll
Founder & Autism Advocate