Direct answer
Rommelse et al. · Leitner, Y. · Rodrigues et al. · Verified 2026-08-10
Quick summary
In brief
Key points
Prevalence and Diagnostic Considerations
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.
Treatment Approaches for Co-Occurring ASD-ADHD
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.
Evidence and sources
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
Frequently asked questions
- Can my child have both autism and ADHD?
- 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.
- Does ADHD medication work for autistic children?
- 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.
- Will the OAP fund services for both autism and ADHD?
- 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.
Where the waitlist stands
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.
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