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Yes, research consistently shows that 50–70% of autistic individuals also meet criteria for ADHD. Since the DSM-5 (2013), clinicians can diagnose both conditions simultaneously. Both conditions can be assessed together through a comprehensive developmental assessment. An additional ADHD diagnosis does not change OAP eligibility — services are based on the autism diagnosis. However, understanding both conditions helps clinicians create more effective treatment plans.
Children with both autism and ADHD often experience more pronounced daily functioning challenges and may benefit from combined behavioural and pharmacological treatment approaches.
Autism and ADHD share several features, which is why they frequently co-occur and can be challenging to distinguish:
Referral to a specialist
Ask your family doctor for a referral to a developmental paediatrician or registered psychologist experienced in both conditions.
Comprehensive assessment
Includes ADOS-2 (autism), ADHD rating scales (Conners/Vanderbilt), cognitive testing, adaptive behaviour assessment, and clinical interviews. Typical cost: $2,500–$5,000 privately.
Integrated report
The assessment report will clarify whether one or both diagnoses apply and provide tailored recommendations for treatment and school accommodations.
Wait times: Public assessment waitlists in Ontario average 1–2 years as of 2025. Private assessments are typically available within weeks but cost $2,500–$5,000 out of pocket. Some families use their OAP core funding to cover private assessment costs.
OAP context: With 87,692 children registered and only 23.1% receiving core services as of December 2025, children with dual diagnoses face the same multi-year wait for OAP services. ADHD medication management can often begin through a family physician while waiting for OAP behavioural services.
Co-occurrence Research
Rommelse, N. N., et al. (2010). "A review on cognitive and brain endophenotypes that may be common in autism spectrum disorder and attention-deficit/hyperactivity disorder." Neuroscience & Biobehavioral Reviews, 34(3), 311-325. The 50-70% co-occurrence rate is widely cited in peer-reviewed literature.
DSM-5 Change
American Psychiatric Association. (2013). Diagnostic and Statistical Manual of Mental Disorders (5th ed.). Removed the exclusion preventing simultaneous autism and ADHD diagnoses.
APA Style:
End The Wait Ontario. (2026). Can My Child Have Both Autism and ADHD? Retrieved March 23, 2026, from https://www.endthewaitontario.com/answers/autism-and-adhd-dual-diagnosisChildren with dual diagnoses face the same multi-year waits for services during critical developmental windows.
Take Action to Help End the WaitCommitment to Accuracy: Our data is verified against official government reports (FAO, MCCSS), peer-reviewed scientific literature, and accessible public records. Last updated: February 1, 2026.
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Verified Facts
Evidence supports autism screening and intervention commencing in the first 2 years of life — earlier identification directly enables earlier intervention during the highest neural plasticity window
1 in 50 — According to the 2019 Canadian Health Survey on Children and Youth, about children and youth aged 1 to 17 in Canada had an autism diagnosis
WHO recommends accessible, community-based early interventions for children with autism — timely evidence-based psychosocial interventions improve communication and social engagement
87,692 — children are registered in the Ontario Autism Program
23.1% — 23,875 children enrolled in Core Clinical Services; 20,293 have active funding agreements ()
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