The effects of a mental illness on a person’s daily life may not be as clear-cut as those of a physical impairment or developmental disability, Pooran said. But he has seen people qualify for the credit based on a mental illness.

The Canadian Medical Association says the government should provide patients and health-care professionals with a “comprehensive information package,” describing the eligibility criteria for government programs, benefits and compensation.

“Additional efforts are required to ensure that forms, such as the Disability Tax Credit Form, provide clearer information and are, most of all, user-friendly for patients,” Canadian Medical Association spokesperson Ziad Saab said.

After reviewing the CRA’s criteria, Stergiopoulos, a psychiatrist, said “adults with mental-health conditions would definitely qualify for disability tax credits.”

But, she added, some of the criteria are “overly restrictive” and could disqualify many people with mental-illness disabilities.

The CRA’s requirements state that a person’s condition must restrict their abilities at least 90 per cent of the time.

Mental disorders can have a “more variable course” than that, but still cause profound disability, Stergiopoulos said.

Gardner, for instance, says she does not suffer the debilitating symptoms of bipolar disorder every minute of the day.

But, because she never knows when mania or depression might strike, she cannot trust herself to engage in many simple activities, for fear her illness may take control.

Canadians applying to the Disability Tax Credit for 2016 can claim up to $8,001.

But recipients can be reimbursed for past years in which they qualified but did not claim the credit, dating back a decade.

A person who qualified in every year since 2007 could be reimbursed up to $66,000, in addition to this year’s credit.

And, once a person with a disability has been approved, they can claim the credit for a dependant, spouse or common-law partner.