What is a developmental disability?

A developmental disability:

  • Is present at birth or develops before 18 years of age
  • Limits a person's ability to learn
  • Is permanent
  • Can be mild or severe

People with developmental disabilities learn, understand or remember things at a slower pace than others. This can affect their language and social skills. It may also mean that they need help with daily life as well as other assistance to be as independent and successful as possible.

Who has a developmental disability?

One percent of Ontarians have a developmental disability. Some people were born with a condition that caused their disability. Others may have had a childhood illness, accident, or other reason for their disability.

People with a developmental disability can still participate fully in their community. They can be great athletes, artists, workers, advocates, neighbours and friends. They're an important part of the community and contribute to the strength of our province.

Confirming Eligibility for Developmental Services

Adults who access services and supports through Developmental Services Ontario must have a developmental disability as defined within the Services and Supports to Promote the Social Inclusion of Persons with Developmental Disabilities Act (2008). To confirm if a person has a developmental disability, we will need to review a copy of a psychological assessment.

Only a psychological assessment or report, completed by a psychologist or psychological associate can be used to confirm that a person has a developmental disability. The assessment or report must consider each of the following:

Cognitive Functioning

  • Cognitive functioning means a person's intellectual capacity including the capacity to reason, organize, plan, make judgments, and identify consequences
  • Cognitive limitations are usually explained using a standardized measurement of intellectual functioning (IQ tests). These test results are reported in the body of a psychological assessment.

Adaptive Functioning

Adaptive functioning means a person's capacity to gain independence and apply skills in everyday life. Skills include:

  • Conceptual - language, reading, writing, money, time,
  • Social - interpersonal skills, social responsibility, self-esteem
  • Practical skills in their everyday life - activities of daily living, occupational skills, use of money, safety


  • The psychological assessment must confirm that the significant limitations in cognitive and adaptive functioning began before the person reached 18 years of age.
  • If the psychological assessment was completed prior to 18 years of age then no more information is needed.
  • If the psychological assessment is completed after 18 years of age the assessment must indicate that the current difficulties were present before age 18 and they are life-long in nature.

Additional Eligibility Requirements

When you call the Developmental Services Ontario agency, we can provide you with information and answer any questions you might have about the eligibility confirmation process.

The Developmental Services Ontario agency is also required to confirm that applicants are at least eighteen years of age. Documents that can be used to confirm age can include but are not limited to:

  • Birth or baptismal certificate
  • Passport
  • Driver's license

We must also confirm that applicants are residents of Ontario. Documents that can be used to confirm residency in Ontario include but may not be limited to:

  • Rental or lease agreement
  • Statement of direct deposit for Ontario Disability Support Program
  • Employer record (pay stub or letter from employer on company letterhead)
  • Mailed bank account statements (does not include automated teller receipt or bank book)
  • Utility bill

Additional Information

Staff at Developmental Services Ontario - South West Region are happy to provide additional information describing the application process, as well as information about services and supports in your community that can assist adults with developmental disabilities and/or their families.

Information can be accessed by telephone, during a face-to-face discussion with one of our staff, from the Developmental Services Ontario website, or using some other method that you would find helpful and effective.

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