Yes, you require verification of your condition from a medical professional. Documentation needs to be from your GP, Specialist, Psychologist, Physiotherapist or other treating professional. They can write a letter or use the Verification form provided by the Disability Service. The documentation from your treating provider should outline the accommodations you require to support your studies.
If you have a specific learning disability you need to provide the report from the psychologist who did the assessment, and it must be from high school age or older. For further information and rationale please refer to the psycho-educational assessment process.