DTC Denied for ADHD? How to Ask CRA for a Review and File an Objection

The envelope from the Canada Revenue Agency is thin, which is never good. The notice of determination says your application for the disability tax credit has been denied. Your clinician filled out the form. You have a diagnosis. You spent weeks on it. And the letter gives two paragraphs of reasons that seem to describe someone else.

A disability tax credit denied for ADHD is common, and it is often not the end. CRA's own process offers two routes back: an informal request for a review with new information, and a formal objection with a hard 90-day deadline. Beyond that sits the Tax Court of Canada, which hears these cases more often than people expect. This post walks through each step, what to send, and what stronger documentation looks like for the mental functions category that ADHD claims fall under.

Nothing here is tax or legal advice for your situation, and the rules change. A free tax clinic, a disability organisation or an accountant who handles DTC files can look at the specific letter with you.

Reading the notice of determination: what CRA actually rejected

The first move is to work out which of three things CRA is saying. The letter will usually point at one of them.

• The restriction was not marked. CRA accepts the diagnosis but concludes the form did not show a marked restriction in mental functions necessary for everyday life. This is the most common reason for ADHD denials: the form described symptoms, not the effect on daily functioning.
• The restriction was not present substantially all of the time. CRA uses a threshold of at least 90 percent of the time, with appropriate therapy, medication and devices in place. A form that says attention is a problem at work or on bad days reads as less than that.
• Duration or practitioner. The impairment must have lasted, or be expected to last, at least 12 months, and for mental functions the certifying practitioner must be a medical doctor, nurse practitioner or psychologist. A form signed by another professional can be rejected on that ground alone.

Also check whether CRA sent your practitioner a clarification letter during the review. CRA often writes to the clinician with follow-up questions, and applications are denied because the questionnaire came back incomplete or not at all.

For the basics of the credit, see our answer on what the disability tax credit is for ADHD and the complete guide to the DTC for ADHD in Canada, which covers the first application.

Step one: request a second review with new information

Before filing anything formal, CRA allows you to ask for the application to be looked at again. It is the faster route when the denial was about the quality of the form.

1. Write a short letter to the tax centre named on your notice, stating that you are requesting a review of your DTC application and that new medical information is enclosed. Include your name, Social Insurance Number and the date of the notice.
2. Enclose the new information. A second copy of the same form gets the same answer. What CRA needs is a letter or amended form from the practitioner that addresses the specific reason in the denial, in CRA's own terms, with examples from daily life.
3. Mail it, or upload it through CRA My Account under submit documents, and keep dated copies of everything.
4. Watch the calendar. The 90-day clock for a formal objection runs from the date on the notice regardless of any review in progress. If the review is slow, file the objection too, to protect the deadline.

Step two: the formal notice of objection and its 90-day clock

A notice of objection is a formal dispute. It moves the file from the DTC unit that denied it to CRA's Appeals Branch, where an officer not involved in the original decision reviews it fresh.

• Deadline. 90 days from the date on the notice of determination. Not from the day you received it.
• How to file. Online through CRA My Account using the formal dispute option, or on paper with Form T400A, Notice of Objection, mailed to the intake centre listed on the form.
• What to write. State the facts and why you disagree, specifically: the form showed a marked restriction in attention and adaptive functioning present substantially all of the time, as described in the enclosed practitioner letter. Attach everything: the original form, the denial, any clarification letter and the new evidence.
• If you missed the 90 days. You can apply for an extension within one year after the deadline, explaining why you could not file in time. Extensions are not automatic, so send the objection and the extension request together, as soon as you can.

Appeals reviews take months. Answer any request from the officer promptly and in writing. The outcome is either an allowance, which grants the credit, or a notice of confirmation, which upholds the denial and opens the door to the Tax Court.

What stronger documentation looks like for mental functions

Most ADHD denials come down to the form. Since the 2021 changes to the DTC criteria, mental functions necessary for everyday life explicitly include attention, concentration, memory, judgement, problem-solving, goal-setting, regulation of behaviour and emotions, adaptive functioning and comprehension. A strong submission describes the restriction in those terms, with concrete examples, and says plainly that it persists substantially all of the time even with treatment.

• Effects, not diagnosis. Not has ADHD, inattentive presentation, but cannot reliably complete a multi-step task such as paying bills or preparing a meal without prompts, on most days, despite medication and therapy.
• Frequency language that matches CRA's. The words substantially all of the time, or at least 90 percent of the time, should appear if they are true. Vague frequency is read as occasional.
• With treatment in place. CRA assesses the restriction that remains after appropriate therapy, medication and devices. The practitioner should say what is in place and describe what persists anyway.
• Duration. At least 12 continuous months. For adults diagnosed late, a statement that the impairment has been lifelong is relevant.
• Corroboration. An assessment report, school records or IEPs, workplace accommodation letters, or a letter from a family member describing daily support. CRA weighs the practitioner's form most heavily, but supporting documents give it something to stand on.

If you do not have a clinician who knows your day-to-day functioning, or you have never had a formal assessment, that is worth fixing before the next submission. Finding Focus provides online ADHD assessment and treatment for adults and teens in several Canadian provinces, with no referral needed; details are on our ADHD services page. Whether a clinician completes the DTC form, and what they conclude, is always their professional judgement.

Tax Court as a last resort, and when it is worth it

If Appeals confirms the denial, you can appeal to the Tax Court of Canada within 90 days of the notice of confirmation. DTC appeals are heard under the informal procedure, designed for people representing themselves, with no lawyer required and a judge who hears directly from you and your witnesses.

Whether it is worth it depends on three things.

• The money. An approved credit can be claimed back up to ten years and opens the door to the Registered Disability Savings Plan and some provincial benefits.
• The evidence. Court is where a detailed practitioner letter and a clear account of daily functioning matter most. If the file is thin, strengthen it at the review and objection stages first.
• Your capacity. Preparing an appeal is a sustained administrative project, which is a hard thing to ask of someone whose claim is about sustained attention. A trusted helper or a disability advocate makes a real difference.

Whatever stage you are at, the ADHD care you paid for in the meantime may still count as a medical expense on your return, independent of the DTC. Our post on claiming ADHD care as a medical expense explains how.

This week: find the notice, circle the date, count 90 days forward and write that date on the fridge. Then call the practitioner's office with two questions: did CRA send a clarification letter, and will they write a letter describing your daily functioning in CRA's terms. The answers decide which route you take.