Sensory Processing Disorder vs Autism: Understanding the Differences
Direct answer
Specific costs, rates, and timelines are unavailable because providers, pathways, and research populations are not directly comparable. Ask the relevant assessment provider for current details.
Why Timing Matters
The wait outlasts the window.
Clinical research (American Academy of Pediatrics; Hyman et al., Pediatrics 2020) identifies birth to age six as the peak neuroplasticity window for autism intervention. Ontario's reported minimum wait is 5+ years for families registered in August 2021 (community-reported, Ontario Autism Coalition, July 2026).
Example: an illustrative child's journey through the Ontario Autism Program
Registered at age 3. Services begin at age 8, after 5+ years for families registered in August 2021 (community-reported, Ontario Autism Coalition, July 2026), most of it inside the intervention window.
| Measure | Age range |
|---|---|
| Early-intervention window (AAP) | Birth to age 6 |
| Example wait using the OAC-reported minimum (registered age 3) | Age 3 to age 8 (5 years) |
| Age when services begin in this example | Past age 6 |
✓ Intervention before 6
Research shows 2× greater gains in cognitive and adaptive functioning. Some children lose their diagnosis entirely. The brain's plasticity makes early therapy dramatically more effective.
◌ Intervention after 6
Reduced neuroplasticity means slower progress, higher lifetime costs, and poorer outcomes. Every year of delay narrows the range of achievable milestones. Ontario's waitlist guarantees this for most families.
Of the 71,263 children on the unfunded backlog, the majority were registered between ages 2 and 4. At the current pace, most will age past 6 before receiving any core funding , missing the window that the American Academy of Pediatrics and every major autism research body identifies as critical.
SourceAmerican Academy of Pediatrics (Hyman et al., Pediatrics 2020) · Ontario MCCSS OAP data via FOI · Wait: 5+ years for families registered in August 2021 (community-reported, Ontario Autism Coalition, July 2026).
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Understanding the Overlap
- Sensory processing difficulties are so common in autism that they were added to the DSM-5 diagnostic criteria in 2013 under the restricted/repetitive behaviours domain. Sensory difficulties also occur in children who are not autistic.
- The overlap creates diagnostic confusion. A child who covers their ears in loud environments, avoids certain food textures, and has difficulty with transitions might be showing sensory processing difficulties, autistic traits, or both. Ask your doctor which assessments fit your child's concerns.
Assessment Pathways in Ontario
- Autism diagnosis requires a qualified professional, such as a doctor (including family doctors and pediatricians), psychologist, psychological associate or nurse practitioner, using the DSM-5 criteria.
- OAP core clinical services funding can pay for occupational therapy, including for sensory needs, once a child registered in the OAP is invited to core clinical services. OAP registration requires a written autism diagnosis. If autism is suspected, pursue a formal diagnostic assessment through your pediatrician. The two assessment processes can proceed in parallel. Children’s treatment centres also provide OT in Ontario public schools.
Frequently asked questions
SPD is not included as a standalone diagnosis in the DSM-5. However, a 2012 American Academy of Pediatrics policy statement noted that occupational therapists increasingly use sensory-based therapies, and said there is no universally accepted framework for diagnosing SPD. Sensory processing difficulties are included within the autism diagnostic criteria. Some clinicians use SPD as a working description for sensory difficulties in non-autistic children.
If your child has sensory processing difficulties along with social communication differences or restricted/repetitive behaviours, you can ask your pediatrician whether an autism assessment makes sense. Ask your doctor about OT referral options for sensory concerns.
A health professional can discuss sensory concerns and whether another assessment is appropriate. Ask your doctor about referral options and what each assessment can answer.
Sources
APA
American Psychiatric Association — DSM-5 Diagnostic Criteria for Autism Spectrum Disorder (2013)
Tomchek & Dunn
Tomchek & Dunn (2007), "Sensory processing in children with and without autism: a comparative study using the Short Sensory Profile," American Journal of Occupational Therapy
Ahn et al.
Ahn et al. (2004), "Prevalence of parents' perceptions of sensory processing disorders among kindergarten children," American Journal of Occupational Therapy
AAP
American Academy of Pediatrics (2012), "Sensory integration therapies for children with developmental and behavioral disorders," Pediatrics, 129(6), 1186-1189
Autism assessment and diagnosis (ontario.ca, updated March 10, 2026)
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Next step near you
Where to be assessed near you
- TorontoHolland Bloorview
- OttawaCHEO
- MississaugaErinoakKids (Mississauga Facility)
- BramptonErinoakKids (Brampton)
- North YorkHolland Bloorview (referral)
- ScarboroughSickKids (referral)
See every Ontario city we track
Assessment routes, local providers and school boards are tracked city by city. Pick the one closest to you.
Where the wait clock starts
A child's place in the Ontario Autism Program queue is set by the AccessOAP registration date. 71,263 children are registered and still waiting for core funding (MCCSS FOI via OAC · May 2026).
Next steps
Keep going with related guidance, tools, and evidence.
Related questions
What Does an Autism Assessment Include in Ontario?
A comprehensive autism assessment includes developmental history, clinical observation, often a standardized tool (ADOS-2, ADI-R), and other tests like cognitive testing when needed.
Sensory Integration Therapy for Autism
OT-based sensory integration therapy addresses sensory processing differences in autistic children. Learn about the evidence, OAP coverage, and what to expect.
Autism Levels 1, 2, and 3: What Do They Mean?
Autism levels 1, 2, and 3 explained: what each DSM-5 support level means and how all three qualify for Ontario Autism Program funding.
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