Last updated: August 2026 | Reviewed by Nainesh Kotak, B.A. (Hons), LL.B.

Our Evolving Understanding of Fibromyalgia

Fibromyalgia was referred to as “muscular rheumatism” in the 1800s and “fibrositis” in the last century. In 1990, the American College of Rheumatology defined “fibromyalgia syndrome” (FMS) for research purposes, and over the past several decades it has increasingly been recognized as a genuine, disabling condition with rheumatologic, neurologic, and chronic pain components.

The specific cause of fibromyalgia remains unknown, but research indicates it originates in the nervous system, causing malfunction in the body’s pain-regulating mechanisms. These abnormalities in the nervous system, muscles, and connective tissue are generally understood to cause the widespread musculoskeletal pain that is fibromyalgia’s primary symptom. Other symptoms commonly include non-restorative sleep, fatigue, mood disorders, cognitive dysfunction, and heightened anxiety about physical symptoms.

Diagnostic criteria generally look for widespread pain across multiple tender-point sites, along with additional symptoms such as:

Neurological symptoms — muscle numbness, tingling, weakness, cramps, headaches, and light or sound sensitivity
Neurocognitive symptoms — reduced concentration, short-term memory loss, difficulty multitasking, and slowed performance (often described by patients as “brain fog”)
Persistent fatigue with diminished physical and mental stamina
Sleep dysfunction — non-restorative sleep, insomnia, or hypersomnia
Autonomic and neuroendocrine symptoms — dizziness, irregular heartbeat, temperature intolerance, and emotional disturbances
Stiffness, often most severe upon waking

Canadian clinical guidelines developed by the Canadian Rheumatology Association and Canadian Pain Society now define fibromyalgia as a neurophysiological condition, with diagnosis generally assigned to family physicians rather than specialists.

Fibromyalgia affects roughly 1.8% of Canadians — an estimated 575,500 people as of 2020, according to Statistics Canada — across all age groups, though risk increases with age, and women are affected roughly six times more often than men.

Fibromyalgia and Disability Claims

Given the disabling effect of widespread, persistent pain, fibromyalgia often results in an inability to work and, in turn, a long-term disability claim. There is currently no cure, though medication, coping strategies, psychological support, and other treatments can help manage symptoms.

Fibromyalgia can significantly affect a person’s ability to function at home, at work, and socially. Symptoms such as chronic pain, cognitive difficulties, and extreme fatigue can interfere with both the physical and mental demands of most jobs. Fibromyalgia symptoms frequently lead to secondary conditions like anxiety and depression as well, which can compound the original disability.

Fibromyalgia can qualify for LTD benefits just as other medical conditions can, provided the symptoms and resulting limitations satisfy the definition of disability in the applicable policy. In practice, however, fibromyalgia claims are sometimes denied on the basis that the claimant hasn’t submitted sufficient medical proof of functional limitation — a particular challenge given that fibromyalgia’s core symptoms aren’t confirmable through imaging or standard lab testing.

Fibromyalgia and the Own Occupation to Any Occupation Transition

This evidentiary challenge can become more pronounced after roughly two years on claim, when many LTD policies shift from asking whether you can perform your own occupation to whether you can perform any occupation you’re reasonably suited for. Because fibromyalgia symptoms like pain, fatigue, and cognitive fog aren’t easily measured through imaging or lab tests, insurers sometimes argue that a claimant could perform a different, less demanding role at this stage — without properly accounting for how these symptoms affect a person’s ability to function reliably day to day.

Learn more about the own occupation to any occupation transition.

How a Disability Lawyer Can Help With a Fibromyalgia LTD Claim

At Kotak Law, our review of a denied or terminated fibromyalgia LTD claim may include:

your longitudinal medical history — how your symptoms and treatment have evolved over time, not just a snapshot
whether your file documents functional limitations specifically, rather than relying on the diagnosis alone
evidence of fatigue, cognitive fog, and other symptoms that affect your ability to work reliably
the strength of evidence from a rheumatologist or your family physician
how the insurer’s demand for “objective” medical proof was applied to your claim
the transition from the “own occupation” to “any occupation” definition, and how it applies to a condition like fibromyalgia
applicable limitation periods
whether a legal claim should be commenced

Frequently Asked Questions About Fibromyalgia LTD Claims

Is fibromyalgia recognized as a legitimate basis for an LTD claim in Canada?
Yes. Fibromyalgia is recognized in the medical and legal community as a genuine condition capable of causing long-term, and even permanent, disability.

Why are fibromyalgia claims often harder to prove than other conditions?
Fibromyalgia can’t be confirmed through imaging or standard lab testing, so claims tend to depend heavily on the claimant’s credibility and the consistency of their treatment history. Establishing a genuine, consistent effort to seek treatment can help support your credibility.

What if my insurer says there isn’t enough objective evidence?
Not every disabling condition produces objective test results. The medical evidence should still document your symptoms, treatment, and specifically how your condition affects your ability to function at work.

What happens to my claim after two years?
Many policies shift to a stricter “any occupation” standard around the two-year mark. Read more about how this transition works.

Does Kotak Law handle fibromyalgia LTD claims across Canada?
Kotak Law represents clients in long-term disability matters throughout Canada. Nainesh Kotak has practised law in Ontario since 1994 and is also called to the bars of Alberta and British Columbia, with the firm continuing to expand its bar admissions across Canada.

Related Long-Term Disability Resources

Speak With a Disability Lawyer About Your Claim

If you were denied LTD coverage for fibromyalgia, or your benefits were unfairly terminated, Kotak Law can review your file and explain what steps can be taken to resolve your claim.

Free consultation. Disability cases are handled on a contingency-fee basis.

Speak With a Disability Lawyer →

About Nainesh Kotak and Rajiv Haté

Nainesh Kotak, B.A. (Hons), LL.B., has practised law in Ontario since 1994 and is also called to the bars of Alberta and British Columbia. Nainesh and his colleague Rajiv Haté are both recognized by the Canadian Lexpert Directory as leading lawyers in long-term disability law.

Nainesh is a Past Chair of the Long-Term Disability Section of the Ontario Trial Lawyers Association (OTLA) and currently serves as Vice President of OTLA.

Together with the firm’s disability lawyers — including Kaity Yang and Avinaash (Avi) Laljie — Nainesh and Rajiv represent clients throughout Canada in long-term and short-term disability disputes involving major Canadian insurance companies.

Fibromyalgia Disability Claims