New here? Start with our 2-minute guide to OAP registration , no sign-up required.
Comorbidity guide
Autism and ADHD co-occur at rates far higher than chance would predict — ADHD commonly co-occurs with autism, and approximately 20-Rate unavailable; the cited research populations and methods differ of those with ADHD also meet criteria for autism. Until 2013, the DSM did not allow both diagnoses simultaneously, meaning an entire generation of individuals had one condition overlooked. Recognizing and addressing both conditions is essential for effective intervention planning in Ontario.
These guides sit within Ontario's autism funding system. The May 13, 2026 OAP administrative snapshot reports 91,974 registered children. A separate Ontario Autism Coalition July 2026 community-reported invitation cohort describes a five-year-plus signal; Ontario does not publish an official average wait.
ADHD commonly co-occurs with autism — a pattern long recognized in the research literature (Leitner, 2014). The overlap is not simply diagnostic confusion: family and twin studies support shared familial and genetic underpinnings for the two conditions (Rommelse et al., 2010).
Diagnostic assessment for dual ASD-ADHD requires careful differentiation of overlapping features. Both conditions can present with difficulty sustaining attention, social challenges, and emotional dysregulation. A comprehensive assessment should include standardized measures for both conditions (e.g., ADOS-2 for autism, Conners-3 or SNAP-IV for ADHD) administered by clinicians experienced in co-occurring neurodevelopmental conditions.
In Ontario, ask each assessment provider whether they screen for both autism and ADHD. Availability and waits vary by provider and region.
Medication for ADHD symptoms (stimulants and non-stimulants) is generally effective in autistic individuals, though response rates are somewhat lower and side effects may be more pronounced than in ADHD alone. A 2019 meta-analysis by Rodrigues et al. found that methylphenidate reduced ADHD symptoms in autistic children with a moderate effect size, but adverse effects (irritability, appetite loss) occurred at higher rates.
Behavioural interventions should address both conditions simultaneously. ABA-based interventions can incorporate ADHD-specific strategies such as organizational supports, task chunking, and reinforcement schedules designed for the shorter attention spans typical of ADHD. Occupational therapy focusing on executive function and self-regulation benefits both conditions.
Ask your Ontario Autism Program provider which goals can be included in your child's plan. Document attention, organization, and impulse-control needs when they affect daily life.
Rommelse et al.
Shared heritability of attention-deficit/hyperactivity disorder and autism spectrum disorder. European Child & Adolescent Psychiatry, 2010; 19(3):281-295
Leitner, Y.
The co-occurrence of autism and attention deficit hyperactivity disorder in children. Frontiers in Human Neuroscience, 2014; 8:268
Rodrigues et al.
Pharmacological interventions for ADHD symptoms in autism spectrum disorders: meta-analysis. J Child Psychol Psychiatry, 2019; 60(7):706-722
Yes. Since the DSM-5 (2013), dual diagnosis of autism and ADHD is recognized. Research shows that ADHD commonly co-occurs with autism. Both conditions should be assessed and addressed in the treatment plan.
Research shows that stimulant medications are effective for ADHD symptoms in autistic individuals, though response rates are somewhat lower than in ADHD alone. Side effects may be more common, so careful monitoring and dose titration are important. Work with a physician experienced in both conditions.
The Ontario Autism Program funds services based on the child's documented needs. Ask your provider whether attention, organization, or impulse-control goals are eligible in your child's plan.
Next Steps
Families navigating autism services in Ontario face a documented multi-year wait. Here is the Ontario data — and a two-minute way to push back, when you are ready.
Related Resources
How long does autism diagnosis take in Ontario?
VerifiedBefore joining the OAP waitlist, Ontario diagnostic waitlists average 12–24 months at public hospitals. This pre-waitlist delay means total time from first concern to therapy often exceeds 5–7 years, an invisible bottleneck in official statistics.
Source: Ontario Autism Program [OAP] · Verify Link
Is private autism assessment faster in Ontario?
VerifiedPrivate autism assessments cost $2,500–$4,000 but reduce wait times from years to weeks. Many families face the choice of paying out-of-pocket to access the OAP sooner or waiting while their child misses the critical early intervention window.
Source: Ontario Autism Program [OAP] · Verify Link
How long do families wait for Ontario autism services?
VerifiedOntario autism wait times for core clinical services now exceed 5+ years (Ontario Autism Coalition, July 2026). Funding invitations are currently reaching families who registered in August 2021 (Ontario Autism Coalition, July 2026 (reported from community intake)). This delay far exceeds the sensitive early intervention window recommended by developmental specialists.
Source: MCCSS FOI via OAC · Mar 2026, FAO Report 2024 · Verify Link
How many children are on the Ontario autism waitlist in 2026?
VerifiedAs 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