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FND, IBS, fibromyalgia, lower back pain

What are the similarities between FND, Fibromyalgia, Irritable Bowel Syndrome (IBS) and other functional illnesses?

chronic fatigue syndrome dr. velazquez fibromyalgia fnd functional illnesses ibs lower back pain Jan 30, 2022

As we have previously reviewed, the most accepted and appropriate term to describe the group of illnesses previously classified as psychogenic, psychosomatic and conversion disorder, currently is functional neurological disorder (FND). Under this category we can find any, and all FUNCTIONAL SYMPTOMS BELONGING TO THE NERVOUS SYSTEM.  

FND however, is located under the umbrella of FUNCTIONAL ILLNESSES (FI), because functional disorders do not only affect the nervous system, but it can also affect many other organs and systems, because as I say often, the nervous system is involved in anything and everything we do, and it has connections to and from all other organs and systems in our body. Let us see some examples of other functional symptoms and illnesses affecting other parts of our organisms, and that would be also classified under the umbrella of functional illnesses:

  • Fibromyalgia is a disease mainly evaluated and treated in the rheumatological offices, and it affects the musculoskeletal system in the form of widespread chronic pain. Fibromyalgia is currently being characterized by some experts as a functional disorder, because when the physicians perform the various ancillary tests in the blood, muscles, joints, bones, tendons, and nerves, they find nothing wrong with the structure and the anatomy of these organs. 


  • Chronic lower back pain in the context of normal anatomy, or out of proportion to any abnormality found in the musculoskeletal structures, is considered a functional disorder too. These patients can present to the orthopedists because the pain appears more linked to the bones, muscles, tendons, and other structures of that area.


  • Irritable bowel syndrome (IBS) is a condition that affects the gastrointestinal tract and is followed by the gastroenterologist. This syndrome is characterized by many experts as a functional problem that takes place in the various pathways and connections between the nervous system and the intestines. Functional dyspepsia on the other hand, is a problem involving digestion and digestive processes, that can cause symptoms such as bloating, stomach pain, early satiety, and other symptoms in the stomach.


  • Some patients present to the Ear, Nose and Throat (ENT) specialist with chronic dizziness, voice problems, sensation of having something stuck in their throats, difficulty swallowing, but the test results and the physical examination do not reveal an anatomical problem; however, these persons often have significant distress and difficulties functioning well during activities involving speech, swallowing, or hearing, just to name a few.


  • Chronic fatigue syndrome is believed to be a manifestation of a functional syndrome because those affected often undergo extensive examinations, are evaluated by multiple professionals such as infectious disease specialists, endocrinologists, neurologists, rheumatologists, and the test results do not reveal any specific cause to explain the patients’ dysfunction.


  • Many cases of intermittent or chronic chest pain that upon testing do not show any significant abnormalities in the heart, the lungs, esophagus and the other structures located in the thoracic area, could also point towards a functional origin, particularly if the person is having multiple symptoms besides pain, such as palpitations, shortness of breath, and nothing wrong is found in the organs and structures of the chest cavity, yet, there are significant symptoms taking place in that region.


  • Symptoms of “chronic Lyme’s disease” or that appear after Lyme’s disease is detected and fully treated, such as fatigue, numbness, tingling, nausea, itching, blurred vision, among others, are believed by many healthcare professionals to also belong to the functional illnesses category, particularly because functional disorders appear more commonly after an organic disease take place, such as an infection, a fracture, or a stroke, to name a few.

As you can see, functional illnesses are not only found in the neurological offices, and do not only include FND, but these conditions can be encountered frequently in all sorts of outpatient clinics, among multiple specialties and subspecialties, such as primary care physicians, gastroenterologists, rheumatologists, infectious disease specialists, endocrinologists, orthopedists, etc. Functional illnesses can also be encountered and diagnosed for the first time in hospitalized patients.

Despite patients with functional illnesses commonly having all these syndromes, and these discomforts, sadly, frequently, doctors find no explanation to their physical conditions. Physicians often perform multiple tests and investigations and discover nothing wrong, so they often think and say: "I do not know what's going on", “I do not know how to treat you”, “there is nothing else I can do for you”, and so you go from doctor to doctor, desperate looking for answers, finding minimal to no relieve, feeling poorly understood (and rightfully so!).

Prognosis studies have shown that when functional illnesses go undiagnosed and untreated, frequently new symptoms appear, in other organs and systems, with various degrees of severity, leaving patients with no option but to go from one specialist to the other, perhaps from an outpatient clinic to the emergency room, to a hospitalization, to even having an unnecessary surgery or procedure, because the truth is that often healthcare professionals feel frustrated, hopeless and anxious too, and their own desperate search may lead them to prescribe empirical medications and procedures, which then complicate matters even more, as each unnecessary treatment or intervention that leads to no improvement or worsening, will add to the confusion of the patient and the doctor, often leading to worsening functional symptoms, traumatic events, and deepening the top-down and bottom-up mechanisms involved in disease production and maintenance.

This situation, unfortunately, often goes on for months, years, or even decades. I have seen patients and clients who have had functional symptoms for 20 years or more, without knowing what it is happening, overlooking the cause of their discomfort, unable to find the necessary support, or the right treatment. Imagine how aggravating and lonely that can feel! And what is worse, without the right diagnosis, or understanding the cause of the illness, without addressing what is causing the symptoms, the patient and the physician cannot take the appropriate measures to completely cure the disease, so the triggers will continue to be present, the dysfunction keeps happening, the symptoms continue to get worse, and even new symptoms appear. All these have been proven in prognostic studies.  

One of the most important reasons why is important to recognize the similarities between all functional disorders, is because the causes and the effective treatments are very similar for all, however they should be personalized for each one of you, and do not only involve cognitive behavioral therapy (CBT) and physical therapy (PT), which have actually showed only moderate benefit in most studies, but on the other hand, there are many new modalities that are being evaluated worldwide by research trials, some of which I talk about during my educational courses and The Holocene Method. As I say often, awareness must be the first step in any healing path.

Let us take some time for reflection now and let us consider: How do you feel about all this? What are your thoughts and opinions? What is your personal experience? Are your functional symptoms affecting various organs and systems? For how long have they been present? How many specialists have you seen? How many tests have you taken? How many treatments have you received? Has the cause of your problems been investigated and found? Have the professionals involved in your care taken the necessary time to investigate them with you?

Unless we truly reflect on these questions and take the time to look at the problems we are facing, deeply, we will not be able to move out of inertia towards skillful action to protect ourselves, our loved ones, and the future generations, because another fact well known is, the frequency of functional illnesses is increasing, and these conditions can be transmitted to our peers and our descendants through cognitive, learning and epigenetic mechanisms, topics which will be discussed during future learning activities.

It is paramount then, for us to remember that:

  • A functional symptom or illness follows the below diagnostic criteria:
    • Symptoms fluctuate in intensity, severity, appearance, and quality
    • Test results are normal or minimally abnormal, not explaining the symptoms
    • Physical examination is normal or minimally abnormal, not explaining the symptoms
    • Symptoms are not explained by any other know medical condition
    • The history and the physical examination findings support the intermittent dysfunctional nature of the problem
  • FI is an umbrella under which functional disorders from any organ and system can be found, including FND.
  • FI can present to all specialties and all settings
  • FI are much more common than previously thought
  • The presence of a functional symptoms or disease DO NOT exclude the co-existence of an organic problem, on the other hand, organic and functional problems often coexist. It is important to always talk to your physician about all your discomfort and any new symptoms that appear during your life.
  • You must educate your doctors, as many still do not know these concepts
  • Friends and family members often do not understand the disease either, so guide them to valuable and trustworthy resources. Remember that the more they know the more they will be able to comprehend you and support you!
  • There is growing scientific evidence explaining and allowing us to recognize these conditions better, but there is a lot that needs to be done still. We need your active participation in order to help you, and others like you around the world!

 Lastly, I would like to remind you that you are not alone! There are many patients with functional symptoms around the world, and many interested healthcare and wellness professionals trying to gain more knowledge so they can be of better service. Every action taken by you has the potential to bring us closer to one-another and by doing so, we will be able to have an international strong movement for the benefit of all sentient beings.

I am waiting for you! This is OUR movement!

At your service,

Yadira Velazquez, MD

Functional Disorders Healing Ally.

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