By Dr. David M. Brady and Danielle Moyer

Fibromyalgia syndrome (FMS) is hallmarked by complex symptoms and difficulty of diagnosis. Studies show that fibromyalgia is properly diagnosed in as low as 34% of cases, meaning that the other 66% were due to other symptoms that mimicked fibromyalgia.1 What causes such an alarmingly high number of misdiagnoses?

The high percentage of misdiagnosed cases are referred to as “Pseudo Fibromyalgia” (pseudo meaning false, or having the appearance of).1 These constitute various disorders cause unknown or undetermined pain (not necessarily widespread pain), but are not FMS. Examples include anemia, hypothyroidism, Lyme disease, functional nutritional deficiencies, mitochondrial energy production deficiency, dysfunctional liver detoxification, joint dysfunction, muscle imbalance, and even postural distortion.2 Why does this occur so often? One significant reason may be that FMS is not based upon any specific laboratory or diagnostic tests. Rather, it is based on symptomatic criteria and medical history. And unfortunately, many conditions or diseases can be associated with fatigue and muscle tenderness, further confusing doctors.

The properly diagnosed cases are often called “Classic Fibromyalgia syndrome”, which follows the specific symptom patterns of FMS. These symptoms include “global” or widespread genuine pain, changes in pain processing, and heightened awareness and sensitivity to stimuli (touch, light, sound). The most pronounced symptom that differentiates FMS from other medical conditions is the pronounced widespread tenderness and extremely low tolerance to sensory stimulation. This is caused by an abnormality of the central nervous system, rather than a primary muscle or soft-tissue dysfunction.3

Separating “Classic FMS” from “Pseudo FMS” is challenging, yet crucial. Elements of diagnosing FMS include an in-depth patient history, physical examination, neurotransmitter evaluation, and differentiation of other diagnoses or pain-related disorders via comprehensive laboratory testing.1

Fortunately, the presence of common risk factors associated with FMS can act as a differentiators between “Classic” and “Pseudo” FMS. These risk factors include…

1. Common comorbidities/conditions

These include symptoms of persistent fatigue, sleep disorders (non-refreshing sleep), headaches, teeth grinding, cold sensitivity, exercise intolerance, cognitive deficits, Raynaud’s phenomenon, irritable bowel syndrome (IBS), and irritable bladder syndrome.3 All of these symptoms suggest increased sympathetic nervous system activity, hence their correlation. In fact, FMS exhibits almost 100% comorbidity with IBS, where FMS patients almost all have IBS.1 Additionally, about 20% to 50% of FMS patients experience significant depression or anxiety.2

When someone has a metabolic disorder masquerading as fibromyalgia, such as thyroid disorders, adrenal stress, or nutritional deficiencies, they typically do not have a sleep disorder, chronic anxiety, or irritable bowel syndrome, which are all associated with classic FMS.1 According to the American College of Rheumatology Diagnostic Criteria for Fibromyalgia, even if a person scores “high” on their FMS questionnaire, the source of their body pain and aches may not be from classic FMS if they do not have at least two symptoms of anxiety, depression, non-refreshing sleep, or irritable bowel syndrome (IBS).4

2. Family history


FMS almost always involves dysregulation and lower levels of serotonin. Evidence shows that individuals can have genetic mutations that impact serotonin levels passed down to them. Research also suggests that within FMS patients, there are associations with lower pain pressure thresholds in families.1

3. History of trauma, abuse, or chronic stress

Trauma can alter the processing of pain and incoming stimuli of an individual. As a result, trauma can frequently cause an excessive stress response, significant and chronic pain, and central sensitization disorders, such as FMS, anxiety and IBS.1 It has been shown that FMS patients have a “significantly higher prevalence of emotional, physical, or sexual trauma, associated with the onset of FMS symptoms.”1 A pattern of progression in classic FMS can be similar to the progression of depression, both of which can be latently triggered by emotional trauma such as a divorce or death in the family. Many FMS patients have experienced childhood trauma, neglect, verbal and emotional abuse, intense psychological trauma, or chronic stress. Lastly, the symptoms of FMS can be triggered by physical trauma, such as a severe car accident, botched surgery, or physical or sexual abuse.1

4. Being a woman

Disorders that cause low serotonin in the body are much more prevalent in women, where fibromyalgia syndrome is 10 to 20 times more common in women than in men. The suspected reason is due to women’s hormonal and nervous systems responding to stress and trauma differently than men’s.3 Research explored the impact of menstruation and hormonal changes as possible factors, but the data is lacking in supporting specific hormonal abnormalities unique to female FMS patients.2

5. Age

According to the Centers for Disease and Control (CDC), FMS can affect people of all ages, including children. However, most people are diagnosed during middle age.5 

These risk factors, including comorbidities and medical history, should be considered along with medical examination and appropriate lab screening tests to lower the alarmingly high trend FMS overdiagnosis in primary care medicine. If you are exhibiting FMS-like symptoms, it is recommended to seek the care of an experienced and specialized medical practitioner in this field to properly differentiate between “Classic FMS” and “Pseudo FMS”, which is easier said than done. 

Dr. Brady does accept and new patients through his Connecticut practice and can provide

remote video consultations via secure Zoom sessions. You can learn more about his practice and find contacts to the front desk for scheduling and to answer any questions on at: 

If that is not an option for you, your next best option is to try and find a clinician trained in the functional medicine model near you at: 

Because a healthcare provider is trained in functional medicine does NOT mean they understand the issues involved in fibromyalgia like Dr. Brady does, but it is probably your next best option and will assure the provider at least understand some of the more subtle metabolic issues that may be in-play in various cases.



  1. Brady DM, Schneider, MJ. Pain and Fatigue: When It’s Fibromyalgia and When It’s Not. Townsend Letter. October 2012;351:44-50.
  2. Brady DM, Schneider MJ. Fibromyalgia syndrome: A new paradigm for differential diagnosis and treatment. Journal of Manipulative and Physiological Therapeutics. 2001;24(8):529-541. doi:10.1067/mmt.2001.118202
  3. Schneider MJ, Brady DM, Perle SM. Commentary: Differential Diagnosis of Fibromyalgia Syndrome: Proposal of a Model and Algorithm for Patients Presenting with the Primary Symptom of Chronic Widespread Pain. Journal of Manipulative and Physiological Therapeutics. 2006;29(6):493-501. doi:10.1016/j.jmpt.2006.06.010
  4. 2011 Modification of the American College of Rheumatology Diagnostic Criteria for Fibromyalgia. Accessed November 16, 2020.
  5. Fibromyalgia. Centers for Disease Control and Prevention website. Reviewed January 6, 2020. Accessed November 16, 2020.