“Maggie’s Panic”: When Fibromyalgia & ME/CFS Symptoms Gang Up

Reprinted with the kind permission of ProHealth: April 13, 2011

This case history of a patient with CFS and fibromyalgia, plus panic attacks fueled by the autonomic dysfunction that is common with both, is excerpted from Dr. Bell’s book Faces of CFS – Case Histories of Chronic Fatigue Syndrome,* published in August, 2000. “Maggie’s Panic” illustrates one aspect of the illness he has studied in patients affected by the ‘Lyndonville Outbreak’ over the years.

MAGGIE’S PANIC

I do not think a hidden neurosis or other psychiatric condition was lurking in Maggie’s subconscious. Her panic was organic in nature; it came on as a result of physiologic, not psychiatric, factors.

Maggie came into my office about two years ago. By then, she had been ill with chronic fatigue syndrome (CFS) for ten years. She was fairly classic for the disease: joint and muscle pain; night sweats; a headache that would not end; severe fatigue. Despite the latter, she could barely sleep at night.

Naturally, the doctors she had seen in the past were unable to explain the strange combination of symptoms that seemed to possess her like some demon from a haunted past. Maggie, in fact, had been to so many doctors, including two psychiatrists, that she had lost count.

Doctors grow suspicious when patients tell them they already have seen several doctors for the same problems; they assume such patients are looking for a medical opinion they like, as opposed to a medical diagnosis. This is called, in the trade, “doctor shopping.” Maggie knew she had been typecast as a shopper, but she was searching for a diagnosis that made sense.

The symptoms that distressed Maggie the most had to do with her heart.

If she took a walk, she developed chest pain and become short of breath. Once, she told me, after taking a very long walk, she had seen a doctor the next day. She looked ragged, as if she run a marathon and come in last. Her resting pulse was too fast – 110 beats per minute. She told the doctor that she was afraid she was having a heart attack, but the doctor surprised her with a diagnosis of panic attack, instead. Panic disorder has long been viewed as a bona fide condition in which the patient experiences panic at inappropriate times.

Chest pain and shortness of breath were just part of Maggie’s ‘heart’ symptoms, however.

• She often had episodes when her heart would race. Her heartbeat wasn’t merely rapid, it felt as if her heart was flopping around in her chest, as if she had drunk a gallon of coffee, but she had given up caffeine years ago.

• Her face would flush and her palms would sweat.

• Her lips would quiver, her hands would tremble, and one of her eyelids would twitch.

Most doctors, if not all, would diagnose what I have just described as panic disorder.

But Maggie also suffered from a constellation of symptoms that were diametrically opposed; in fact, they were remarkably akin to the state of being comatose.

• She was exhausted to the point of being unable to walk. She showered seated on a lawn chair because she could not stand, for instance; she slept on the couch in her living room because she was unable, at times, to climb the stairs to her bedroom.

• Another coma-like symptom had to do with the way her intellect was dulled. While driving, she sometimes couldn’t remember whether green meant stop or go. Nor could she recall the names of members of her family, or remember a seven digit telephone number – even if it happened to be her own. She found the dialogue on afternoon soap operas incredibly confusing, like a foreign language. Everyone spoke so fast!

• Her body felt leaden, and curiously toxic; she felt a certain kinship with Chernobyl’s radiation sickness victims.

• Her bowels couldn’t decide between coma or panic; they alternated between constipation and diarrhea.

In truth, her entire body couldn’t decide whether it was in a panic or a coma.

At night, when she awoke drenched in sweat, her heart pounding, it was as if panic was awakening her from her coma. There seemed to be no middle ground. Her doctors told her all these symptoms were ‘due to stress.’ To one such doctor, Maggie commented that, aside from the fact that she had lost her job and her husband, that she was bankrupt, and that she was often too weak to climb the stairs of her house, she really had no stress at all.

Our bodies respond to stressful events with the release of adrenaline from the adrenal glands. Adrenaline activates the body’s primal “fight or flight” response. It is a natural stimulant, resulting in a sudden rush of energy to deal with the crisis at hand. Panic is appropriate in times of danger, and adrenaline will give someone the strength to run, if that’s the best choice, or fight. A cave man confronted by a saber tooth tiger might choose to run; the student faced with final exams might choose to knuckle down and study.

Of course, after the adrenaline rush, we are left exhausted and weak, but the crisis is over and with a little rest we are good as new. This, in fact, is the key difference between panic disorder and CFS. Patients who have panic disorder may have relatively normal activity and energy when there is no panic. CFS patients never achieve a normal level of activity, no matter how much they rest or what measures they take to relieve stress. Take a person with CFS and put them on a sunny beach for a day, and their fatigue will not go away, nor will their panic-like symptoms.

Doctors and researchers have long experienced difficulty differentiating CFS [or the dysregulated autonomics of fibromyalgia (1,2,3)] from simple anxiety.

It is true that many persons with CFS experience anxiety. But because CFS patients tend not to have obvious, diagnosable psychiatric illnesses, I suspect that when panic occurs in CFS patients, the cause is physiological, not psychiatric. Whatever else this disease does to the human brain, it includes agitation in its repertoire.

That first time I evaluated Maggie, I realized her medical history was consistent with both CFS and panic disorder, however. In fact, if I were to follow the strict guidelines that the government has laid down regarding CFS, I would not diagnose Maggie with CFS. That’s because research criteria in use today are designed to create a homogeneous population of CFS patients for research purposes.

From clinical experience, however, Maggie’s tender lymph nodes, sore throat, endless headache, and intellectual difficulties were not consistent with a diagnosis of panic disorder. From a clinical point of view the most accurate diagnosis I could render for Maggie was both panic disorder and CFS.

Maggie didn’t really care about the label; she wanted to get at the basis of her symptoms.

Together, we decided to try some of the newer tests for CFS, tests involving the autonomic nervous system. In particular, we would look at the blood vessels and the heart’s ability to pump blood throughout the body. By the time I met Maggie, I had already learned that many CFS patients had low levels of circulating blood in their bodies, an abnormality sometimes accompanied by pulse and blood pressure changes when standing.

The medical term used for this is “orthostatic intolerance,” meaning, simply enough, a worsening of symptoms when in the upright position.

In many medical illnesses, the patient will feel ill regardless of whether he or she is lying down or standing up. With CFS, patients will say, “I feel so exhausted I have to lie down.” For 15 years, nearly every patient with CFS has said this sentence, and I, as well as most other doctors, have misinterpreted it. No wonder this illness is so poorly understood. People should not be tired from standing up for 15 minutes.

We have concentrated on the word “exhausted,” but the key words are, in fact, “lie down.”

The terms “fatigue” or “exhausted” don’t even really describe the unpleasant sensation experienced. “Collapse” is more accurate. What the patient with CFS is really saying is “If I don’t lie down, I am going to collapse.” Medically, the appropriate term is “pre-syncopal,” meaning the state which occurs prior to fainting.

Maggie agreed to allow me to test her orthostatic tolerance, her ability to function during quiet standing.

During a physical exam, she had two abnormalities:

• Fibromyalgia tender points in her muscles

• And difficulty maintaining her balance standing with her eyes closed, a common finding in patients with CFS.

The practical expression of this finding is that patients with CFS are frequently unable to stand for periods in a hot shower. The heat of the water in the shower makes standing more difficult than normal, and often patients will have to go to bed after a simple shower. Sometimes, persons with CFS will put a chair in the shower even though they may be able to walk around the kitchen for ten minutes. A curious, but important detail that Maggie related, implying that heat somehow worsened the process.

The first test we did was very simple, a test of concentration done on two different days, once while standing for 15 minutes and once after lying down for the same length of time.

One of the most prominent symptoms of CFS is the cognitive impairment. Patients will have difficulty with confusion, short term memory, doing simple calculations, and remembering names or telephone numbers. Sometimes this is so severe that concern is raised about dementia or senility. The hardest thing for a patient with CFS is “double tasking.”

My son has amazing powers of concentration. He can be in his room doing his homework, listening to rock-and-roll music while the TV, without sound, shows a football game. I made many vain attempts to inform him that it is not possible to do his homework that way, but his grades were good, and studying this way seemed to do little harm. He was able to “multiple task,” just like I do when I talk on the car phone, drive, and find a quarter for the toll booth, all at the same time. For my son, he probably used 80% of his brain studying, 19% enjoying the music, and 1% watching the football game. Most shows on TV, the sitcoms, can be enjoyed with even less dedicated brain function.

Double tasking is one of the first things to go in CFS.

The test we gave to Maggie was the coding test of  the WISC, a standard intelligence test. In this test, a series of simple codes are made for numbers between 0 and 9, the code printed at the top of the page. The test involves finding, or remembering, the codes for a list of numbers, and scoring is done by adding up the correct coding accomplished in two minutes. It is an annoying little test.

After lying down, Maggie did the test, getting 55 right in two minutes, a normal amount. A week later we repeated the test after standing, and she was able to get only 40 correct, a 20% drop. We have been testing this with healthy persons, and found that, in general, they do as well standing as after lying down.

Maggie’s cognitive problems are related to the position she is in before the test. When horizontal, she does well; after standing, she is dull as a melon. This correlates to another curious detail often found in the history taking of someone with CFS – they read lying down. Most healthy persons prefer to read sitting up.

We measured Maggie’s circulating blood volume at a nearby hospital, and like 80% of our CFS patients, she was low, or as she would later say, “down a quart.”

This finding seems to mesh with the difficulty standing; gravity makes it difficult for blood to get up to the brain, and if the circulating blood volume is low, it should affect brain blood flow. And the mechanism of CFS may be that simple: decreased blood flow to the brain. We don’t know if animals can get CFS, but if they do, giraffes would be in big trouble.

The next test was the most exciting for me, the most unpleasant for Maggie. We call it “orthostatic testing” and it can be done in any doctors office.

It is a simple test, perfected by Dr. David Streeten (4), and described in Andrea Thompson’s case. The patient lies down for 10 minutes during which the pulse and blood pressure are taken. Then during a half hour of quiet standing the pulse and blood pressure are measures every five minutes along with observations of what the patient is experiencing.

Maggie’s blood pressure and pulse were normal while lying down, and she was feeling relatively well – it was a good day for her. We measured the amount of adrenaline in her blood while lying down and it came back at 350, a normal level. The first ten minutes standing were not bad for Maggie, although she started feeling tired. Then she described pain in her legs, lightheadedness, and spiraling fatigue. Her palms were sweaty, and I saw her grow visibly pale. Most significantly of all, she became agitated, and, eventually, she became panicked.

The pulse and blood pressure measurements began to change. When Maggie said she could no longer stand, we terminated the test, I did not want her to pass out on the floor. Her pulse had risen to 140 beats per minute, 80 more than when she had started, and her blood pressure had skyrocketed, almost to levels that could cause a stroke.

As soon as Maggie lay down, we drew a second blood sample to measure her adrenaline again. I also gave her an infusion of saline water. Normally, saline is the last thing you want to give someone with high blood pressure, but I already knew Maggie had abnormally low circulating blood volume.

The elevation of her blood pressure had to be due to a constriction of the blood vessels, a compensation mechanism that would help circulate the blood to her brain. The fast pulse reflected the same problem: Her autonomic nervous system was trying to make her heart beat faster in order to circulate blood.

While standing, Maggie began to fall apart because her brain was deprived of blood.

A healthy person has several compensatory mechanisms that automatically keep blood flowing to the brain indefinitely. Maggie might look healthy to a casual observer, and the private disability company she had paid into for many years prior to becoming ill said that she was just fine.

But imagine Maggie trying to work an eight hour day when she had such dramatic changes in pulse and blood pressure after just 20 minutes standing. I would definitely not want her to be my bank teller trying to make change after standing for two hours.

Maggie’s compensatory mechanisms were impaired. All but one, that is: adrenaline production.

The body produces adrenaline to compensate for impaired blood flow to the brain. In fact, it is one of the body’s most effective ways of improving circulation, which is why it is called the “fight or flight” mechanism.

Perhaps the most significant finding we made that day had to do with Maggie’s adrenaline. Her adrenaline level had risen to 1450, way above normal, when she had been forced to stand for 20 minutes. Maggie’s body was pumping out adrenaline like mad just to compensate for the crisis of quiet standing.

Adrenaline has one drawback: It causes anxiety.

I believe now that Maggie’s panic was simply due to elevation of her adrenaline levels in an attempt to compensate for impaired blood flow to the brain. I do not think a hidden neurosis or other psychiatric condition was lurking in her subconscious. Her panic was organic in nature; it came on as a result of physiologic, not psychiatric, factors. Panic is appropriate during a crisis, but not during quiet standing.

The surge of adrenaline has several drawbacks. First, it doesn’t work very well. If it had, Maggie would feel wonderful, like the burst of energy after having a cup of coffee in the morning after a good night’s rest. It may be that the adrenaline keeps her up longer, but the price is fatigue. A healthy person will notice that after a crisis, a near car accident for example, the surge of adrenaline is followed by profound exhaustion. Chronic stress will leave a person drained and tired, but recovery occurs quickly once the stress is removed and good rest is supplied.

Maggie’s fatigue is due to a combination of decreased blood flow to the brain and the surge of adrenaline her body produces to attempt to remedy the problem.

Suddenly, there were several medical diagnoses I could give Maggie.

Technically speaking, she had chronic fatigue syndrome, fibromyalgia pain and tender points, idiopathic hypovolemia (decreased blood volume), postural orthostatic tachycardia, orthostatic narrowing of the pulse pressure, orthostatic diastolic hypertension, and hyperadrenergic orthostatic intolerance.

Maggie was not displeased; literally overnight, she had gone from being a hypochondriac to having seven medical diagnoses.

Research into blood volume and brain blood flow is in its infancy. Nevertheless, while we are still in the dark as to what initiates these problems, breaking CFS down into its many parts may allow us to develop specific diagnostic tests for the disease.

Moreover, Maggie’s testing results inspire theoretical treatment options. If we could somehow increase blood flow to the brain and deliver more oxygen to brain tissue, the symptoms of impending collapse should improve. The need for the adrenaline surge would be removed, so the postadrenaline exhaustion would also disappear. In concept, that is.

The co-existence in CFS patients of simultaneous coma and panic symptoms is no longer paradoxical.

Doctors and researchers who assume panic disorder is caused by psychiatric problems exclusively have been looking at the phenomenon in an overly simplistic way. The same chemical mediators that are present in emotionally stressful situations are also the same chemical mediators that help circulate the blood. A test would be to find a way to improve the blood circulation in the brain.

We started with a drug to expand her blood volume, and Maggie’s response to treatment made me so excited that my socks started rolling up and down all by themselves.

Peter Rowe and his colleagues at Johns Hopkins made an important discovery in 1996 after discovering that patients with CFS would faint when tilted upright on a tilt table. They treated their patients with a drug called fludrocortisone (Florinef™), which works by increasing salt and water retention by the body, thus raising blood volume.

I had tried Florinef in many of my patients, and it improved their symptoms about one-third to one-half the time. In my experience, adolescents and those with milder illness responded best to this treatment. The drug helped Maggie: her rapid pulse slowed down, her sleep improved, and she felt slightly more energy. Her panic nearly disappeared.

The concept that a presumably psychiatric symptom – panic – would be helped by a drug which increases circulating blood volume is hard to believe. But it happened to Maggie. Her panic was clearly caused by CFS and its concomitant blood volume deficits, not the other way around. I was encouraged by these changes, but my socks had not yet started rolling, the surprise was yet to come.

Maggie and I talked almost every day during this trial, and we decided to push the therapy a little further by adding salt tablets, hopefully to augment the response.

Two days after adding salt tablets, Maggie returned to “normal.”

At first, I didn’t know what Maggie meant by “normal.” Did she feel a bit better? No, she was reporting complete recovery, normal for the first time in ten years. It was as sudden as a switch being thrown; she described her transformation as “awakening from a dream.” Her thinking was crystal clear. She walked for two miles that first day, smelling the flowers of spring. The whole feeling of illness, the malaise, was gone.

Unfortunately, her recovery was brief. Thirty-six hours later, she began slipping back to her former state, minus the panic, and she has remained in that particular jail cell since then.

We have tried 20 different treatments, raising and lowering doses of this and that, but she has not regained her freedom. In retrospect, the memory of 36 hours of freedom remains a cruel reminder of how nice it feels to be healthy.

The importance of Maggie’s experience to me is a confirmation of a long held belief that CFS is a reversible state, even after ten years.

Not just treatable by reducing some of the symptoms, but reversible. Her return to health was short lived, but it occurred. If she had permanent damage to her brain, I do not think the 36 hours would have been possible.

What is so frustrating is the fact that this state could not be maintained, even though we tried treatments that pushed so much blood into her brain that her skull was ready to explode. Maggie has been a good sport about all of this. Each treatment attempt was discussed in detail and she was eager to take the steps.

While disappointed that we have not been successfuI I see the problem a little differently now. By expanding blood volume it is possible to make some improvements, but not all the time. Even with Maggie’s dramatic 36 hours, the response cannot be maintained even if the blood volume is returned to normal or even elevated levels.

The problem must be in the blood vessels themselves. They must be constricted so tight in the brain that little blood gets through. Perhaps it is one of the hormones that constricts blood vessels. Perhaps an infection of the blood vessels. Perhaps it is an excessive sensitivity of the blood vessels to adrenaline.

Hopefully, this story will soon have a new and more encouraging ending. CFS is a devastating physiologic process that undermines the body’s energy and the brain’s cognitive ability, but I believe that full recovery will someday be possible.

We await the next step, the step that will make Maggie’s precious 36 hours stretch into days, months and years. There is so much to study in this illness, and so much to be gained. Science needs to recognize the importance of CFS, embrace its difficult paradoxes, and get to work.

• CFS is not an isolated, rare illness nor is it an illness behavior for lazy people.

• The consequences of this illness weigh heavily on not only the victim, but also on family, community and society.

• Its tentacles seem to reach across boundaries, blurring the lines between other neurological and immunological disorders.

CFS, and the patients who suffer from it, have a great deal to teach those of us who have made medicine our life. Once researchers unravel the physiologic mechanisms of this illness, the discoveries will help unravel basic mechanisms of unnumbered other diseases.

– Dr. David S Bell, MD, Lyndonville, New York, August 15, 2000

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* This article is excerpted with kind permission from Dr. Bell’s classic book Faces of CFS – Case Histories of Chronic Fatigue Syndrome; © David S Bell, MD, 2000.

Knowing or not knowing: the practical and moral complexity of diagnostic-seeking pathways in situations of medical uncertainty

Abstract:

In this paper, we discuss the practical and moral complexities of diagnostic-seeking pathways for three uncertain medical conditions: fibromyalgia, myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS), and long COVID. We analyse qualitative data collected in the UK between 2023 and 2025, comprising in-depth interviews with medical professionals, researchers, and patients, as well as documentary sources.

Drawing on the anthropology and sociology of diagnosis, this paper discusses how chronic illness can be marked by challenging and unstable pathways, influenced by the organisation of the medical system and the resources patients have to navigate it. Diagnoses further do not guarantee a solution to the condition, and can, on the other hand, produce stigma. Medical professionals recognise the uncertain nature of these conditions and emphasise how diagnosis can play an instrumental role in providing patients with access to therapies, benefits, or acceptance. Patients discuss the complexity of the strategies they deploy not only to obtain a diagnosis but also to navigate the practical and moral complexities associated with their condition.

Analysing the practical and moral complexity of diagnostic-seeking pathways represents a way to enrich anthropological reflections on diagnosis by demonstrating how this key concept of biomedicine is strongly influenced by social, economic, and moral, as well as biological, factors.

Source: Greco C, Cross S. Knowing or not knowing: the practical and moral complexity of diagnostic-seeking pathways in situations of medical uncertainty. Anthropol Med. 2026 Sep 25:1-16. doi: 10.1080/13648470.2026.2709278. Epub ahead of print. PMID: 42788232. https://www.tandfonline.com/doi/full/10.1080/13648470.2026.2709278 (Full text)

DNA methylation: unifying framework for complex chronic conditions

Abstract:

Complex chronic conditions represent a growing health burden that is poorly understood and inadequately managed within current health systems. This review focuses on the potential of epigenetic DNA methylation to provide a pathway for better understanding of four closely related conditions: myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS), long COVID (LC), fibromyalgia (FM), and hypermobile Ehlers-Danlos syndrome (hEDS).

These conditions have extensive overlapping symptoms, suggesting shared underlying pathophysiological mechanisms. Epigenetic regulation, particularly DNA methylation, provides a powerful framework for comparative and longitudinal studies across these clinically overlapping conditions.

Here, we synthesise evidence from current DNA methylation studies in ME/CFS, LC, and FM, and consider how an integrated cross-condition approach could advance mechanistic insight, enable diagnostic stratification, and improve patient outcomes.

Source: Sharma S, Rodger EJ, Chatterjee A, Tate WP. DNA methylation: unifying framework for complex chronic conditions. Trends Genet. 2026 Sep 24:S0168-9525(26)00221-0. doi: 10.1016/j.tig.2026.09.001. Epub ahead of print. PMID: 42786072. https://www.cell.com/trends/genetics/fulltext/S0168-9525(26)00221-0 (Full text)

Micronutrition as a Therapeutic Strategy for Mitochondrial Dysfunction in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome and Fibromyalgia: A Narrative Review

Abstract:

Fibromyalgia and myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) are chronic multisystem disorders characterized by persistent fatigue, pain, cognitive dysfunction, sleep disturbances, and reduced quality of life. Increasing evidence implicates mitochondrial dysfunction, oxidative and nitrosative stress, immune dysregulation, and altered redox and nicotinamide adenine dinucleotide (NAD+) metabolism as interconnected mechanisms contributing to fatigue, although the strength of evidence varies across these pathways. Micronutrients are essential components of mitochondrial bioenergetics, antioxidant defense, and immune-metabolic regulation.

This narrative review critically examines the mechanistic and clinical evidence supporting mitochondrial-oriented micronutritional interventions in fibromyalgia and ME/CFS, including NAD+ precursors, B-complex vitamins, magnesium, coenzyme Q10, alpha-lipoic acid, GlyNAC, L-carnitine, pyrroloquinoline quinone, taurine, and creatine. Mechanistic plausibility is distinguished from clinical efficacy, as disease-specific randomized controlled evidence remains limited for several interventions. We further discuss biomarkers, metabolic phenotyping, and precision nutrition within a systems-based micronutrition framework.

Finally, we present the rationale for a future randomized, double-blind, placebo-controlled trial in fibromyalgia patients with clinically significant fatigue, which is planned for 2027, subject to ethics approval and prospective registration, as a strategy for future clinical validation.

Source: Abanades S, Fernández I, Capdevila N, Cardona F. Micronutrition as a Therapeutic Strategy for Mitochondrial Dysfunction in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome and Fibromyalgia: A Narrative Review. Nutrients. 2026 Aug 19;18(16):2702. doi: 10.3390/nu18162702. PMID: 42654282. https://www.mdpi.com/2072-6643/18/16/2702 (Full text)

Efficacy of Low-Dose Naltrexone in Women With Fibromyalgia Syndrome: A 12-Month Randomised, Double-Blind, Placebo-Controlled Single-Centre Clinical Trial (INNOVA Study)

Abstract:

Background: Low-dose naltrexone (LDN) has been used off-label for fibromyalgia syndrome (FMS) for over a decade, supported by small crossover trials. The INNOVA study evaluated the safety and efficacy of LDN 4.5 mg versus placebo on pain intensity over 12 months in women with FMS.

Methods: In total, 98 women with FMS were randomised to LDN 4.5 mg/day (n = 48) or placebo (n = 50). The primary outcome was change in pain intensity (NRS 0-10) from baseline to 3 months in the intention-to-treat population. Secondary outcomes included functional impairment (FIQR), anxiety-depressive symptoms (DASS-21), cognitive impairment (MISCI), disability (WHODAS 2.0), pathological worry (GAD-7) and impression of change (PGIC/PSIC), assessed at baseline and at 3, 6 and 12 months. Perceived treatment allocation and safety were also assessed.

Results: At 3 months, mean change in pain intensity was -0.33 points with LDN and -0.64 with placebo, with an adjusted between-group difference of 0.49 (p = 0.236, d = 0.19). Secondary outcomes showed minor and inconsistent changes, with low and similar responder rates (p = 0.219-0.954). Exploratory analyses suggested some improvement among participants who believed they had received LDN, although effects were inconsistent. Adverse events, predominantly mild and transient, were reported by 33 (68.8%) participants in LDN and 36 (72%) in placebo, and no treatment-related serious events occurred.

Conclusions: LDN was well tolerated but did not demonstrate a clinically meaningful benefit over placebo for pain-related outcomes, underscoring the need for more effective pharmacological treatments.

Significance statement: This RCT provides the first long-term evidence on the efficacy and safety of LDN in FMS. LDN (4.5 mg), administered as an add-on treatment, has a favourable safety profile, but the findings indicate that it does not produce clinically meaningful improvements in FMS symptoms compared to placebo at short- or long-term follow-up. These findings contribute to the growing body of evidence questioning its clinical utility.

Source: Rodríguez-Freire C, Navarrete J, Rozadilla-Sacanell A, Sanabria-Mazo JP, Del Pino-Gaya B, Borràs X, Feliu-Soler A, Luciano JV. Efficacy of Low-Dose Naltrexone in Women With Fibromyalgia Syndrome: A 12-Month Randomised, Double-Blind, Placebo-Controlled Single-Centre Clinical Trial (INNOVA Study). Eur J Pain. 2026 Jul;30(6):e70321. doi: 10.1002/ejp.70321. PMID: 42385209; PMCID: PMC13322712. https://pmc.ncbi.nlm.nih.gov/articles/PMC13322712/ (Full text)

Shared genetic risk between functional somatic syndromes, internalizing disorders, and immune-mediated diseases: a twin-sibling study

Abstract:

Functional somatic syndromes frequently co-occur with internalizing disorders such as anxiety disorders and major depressive disorder. Both show familial associations with immune-mediated diseases. Here, we estimate genetic and environmental contributions to functional somatic syndromes and their overlap with immune-mediated diseases, with internalizing disorders included for comparison.

The study sample consisted of 6,097,372 Swedish twins, full siblings, and half-siblings born between 1945 and 2003. From nationwide registers covering inpatient, outpatient and primary care, we extracted ICD diagnoses of myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS), fibromyalgia (FM), irritable bowel syndrome (IBS), major depression, anxiety disorders, and immune-mediated diseases (consisting of autoimmune and autoinflammatory diseases).

We used bivariate twin-sibling structural equation modeling to estimate genetic and environmental correlations. We found that the heritability of functional somatic syndromes and internalizing disorders ranged from 15 to 44%, with the unique environment explaining 49-84% of the variance. We estimated the heritability of immune-mediated diseases at 37% (95% CI 36-38%), with a unique environmental component of 63% (95% CI 62-63%). Regarding the genetic correlations with immune-mediated diseases, fibromyalgia showed the strongest genetic correlation (rA = 0.52, 95% CI 0.45-0.63), IBS, ME/CFS, and major depression showed more modest genetic correlations (rA range 0.19-0.29), and anxiety disorders showed minimal genetic correlation (rA = 0.04, 95% CI 0.00-0.08).

In summary, fibromyalgia, and to a lesser degree other functional somatic syndromes and major depression, share genetic risk factors with immune-mediated diseases. These findings suggest that immune-related genetic risk factors contribute to the etiology of fibromyalgia and, to a lesser extent, other functional disorders and major depression.

Source: Steen OD, Ohlsson H, van Ockenburg SL, Kendler KS, Rosmalen JGM, Sundquist K, van Loo HM. Shared genetic risk between functional somatic syndromes, internalizing disorders, and immune-mediated diseases: a twin-sibling study. Brain Behav Immun. 2026 May 25:106837. doi: 10.1016/j.bbi.2026.106837. Epub ahead of print. PMID: 42190845. https://www.sciencedirect.com/science/article/pii/S0889159126005854 (Full text)

Myalgic encephalomyelitis/chronic fatigue syndrome and fibromyalgia – overlap, differences, and emerging insights

Abstract:

Background: Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) and fibromyalgia (FM) are debilitating chronic illnesses with considerable symptom overlap. Their symptoms include profound fatigue, widespread pain, post-exertional deterioration, sleep disturbance, dysautonomia, and cognitive impairment. These illnesses frequently co-occur; ME/CFS often develops first, particularly after infection. This overlap creates a diagnostic grey area and contributes to severe reductions in quality of life. Despite these shared features, key distinctions remain essential. ME/CFS is characterised by post-exertional neuroimmune exhaustion (PENE)/post-exertional malaise (PEM), a hallmark of post-exertional worsening and multisystem involvement. Contrastingly, FM centres on chronic widespread pain and symptom variability. It is not characterised by PEM/PENE or the same extent of system dysfunction as ME/CFS. Both disorders lack a definitive biomarker as of 2025. Thus, diagnosis remains clinical and supported by objective tests where available.

Main body: Although immune dysregulation is common in patients with each condition, distinct immune signatures have been observed. ME/CFS is characterised by fluctuating pro- and anti-inflammatory cytokine levels and a frequent reduction in natural killer (NK) cell function; this is consistent with immune exhaustion. Patients with FM exhibit elevated IL-6, IL-17 A, and IL-4 levels, and a broader immune imbalance linked to pain amplification rather than immune collapse. Viral infections do not directly cause either condition, but commonly act as triggers. Shared mechanisms, such as spinal reflex arc activation and microglial sensitisation, suggest a common pathway mediated by proprioceptor-induced microglial activation for chronic pain. ME/CFS causes autoimmunity-like processes, whereas evidence of autoimmune drivers for FM is limited. Gut microbiome studies have revealed reduced microbial diversity in patients with ME/CFS. Moreover, the two disorders are characterised by shared, yet distinct, microbial alterations.

Conclusion: Given the chronic and debilitating nature of ME/CFS and FM, prevention and early intervention remain crucial, but understudied. Health education, workplace adaptations, and early diagnostic pathways may substantially reduce the disease burden. Many patients are outside formal healthcare systems. Therefore, digital tools such as symptom-tracking apps, biosensors, remote testing, and assistive technologies are becoming central to disease management and monitoring. These approaches support a transdiagnostic, patient-centred model capable of addressing both conditions and reaching populations that remain underserved.

Source: Murovska M, Krumina A, Araja D, Kujawski S, Zalewski P, Nora-Krukle Z, Berkis U. Myalgic encephalomyelitis/chronic fatigue syndrome and fibromyalgia – overlap, differences, and emerging insights. J Transl Med. 2026 Feb 20. doi: 10.1186/s12967-026-07889-6. Epub ahead of print. PMID: 41715182. https://link.springer.com/article/10.1186/s12967-026-07889-6 (Full text available as PDF file)

Use of artificial intelligence and machine learning for the management of fibromyalgia: a scoping review

Abstract:

Background: Fibromyalgia (FM) is a complex and multifactorial syndrome characterized by widespread pain, fatigue, cognitive impairment, and other systemic symptoms. The absence of specific biomarkers and the heterogeneous clinical presentation pose significant diagnostic challenges.

Objective: This scoping review aims to explore the current applications of artificial intelligence (AI) and machine learning (ML) in the diagnosis and clinical management of FM.

Methods: A systematic search was conducted in PubMed, EMBASE, and the Cochrane Library using defined keywords related to FM and AI/ML. Studies were included if they addressed ML applications in FM patients. Following PRISMA-ScR guidelines, 43 studies published between 2011 and 2024 were included and analyzed for ML techniques used, diagnostic targets, data types, and clinical relevance.

Results: As expected, the majority of studies done so far focused on improving diagnostic accuracy through supervised algorithms such as support vector machines, neural networks, and ensemble models, as well as unsupervised clustering and dimensionality reduction techniques. Notable findings include the identification of neurophysiological signatures via fMRI, gene expression patterns, retinal imaging changes, and metabolomic biomarkers that distinguish FM patients from controls. For instance, one study investigating circulating microRNAs used a Random Forest model to identify 11 microRNAs (e.g. hsa-miR-28-5p, hsa-miR-29a-3p, hsa-miR-150-5p) capable of differentiating patients with FM, ME/CFS, and healthy controls, suggesting their potential as biomarkers for more accurate diagnoses. Reported model accuracies ranged from 82% to 100%, although most studies were pilot-based with small and imbalanced samples, limiting generalizability.

Conclusion: AI and ML offer promising tools to overcome longstanding limitations in FM diagnosis and treatment. While current findings demonstrate significant potential, larger, multicenter studies with rigorous validation protocols are essential to finally establish these approaches as clinically reliable solutions.

Source: Clempi Almeida E Silva AL, Reis VHPF, Lamoglia ASA, Souza Desidério C, Freire Oliveira CJ. Use of artificial intelligence and machine learning for the management of fibromyalgia: a scoping review. J Man Manip Ther. 2026 Feb 17:1-17. doi: 10.1080/10669817.2026.2630999. Epub ahead of print. PMID: 41700030. https://pubmed.ncbi.nlm.nih.gov/41700030/

Hypermethylation of OPRM1: Deregulation of the Endogenous Opioid Pathway in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome and Fibromyalgia

Abstract:

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) and fibromyalgia (FM) are debilitating disorders with overlapping symptoms such as chronic pain and fatigue. Dysregulation of the endogenous opioid system, particularly µ-opioid receptor function, may contribute to their pathophysiology. This study examined whether epigenetic modifications, specifically µ-opioid receptor 1 gene (OPRM1) promoter methylation, play a role in this dysfunction.
Using a repeated-measures design, 28 ME/CFS/FM patients and 26 matched healthy controls visited the hospital twice within four days. Assessments included blood sampling for epigenetic analysis, a clinical questionnaire battery, and quantitative sensory testing (QST). Global DNA (hydroxy)methylation was quantified via liquid chromatography–tandem mass spectrometry, and targeted pyrosequencing was performed on promoter regions of OPRM1, COMT, and BDNF. ME/CFS/FM patients reported significantly worse symptom outcomes.
No differences in global (hydroxy)methylation were found. Patients showed significantly higher OPRM1 promoter methylation, which remained after adjusting for symptom severity and QST findings. Across timepoints, OPRM1 methylation consistently correlated with BDNF Promoter I and Exon III methylation. This is, to the best of our knowledge, the first study examining OPRM1 methylation in ME/CFS/FM. Increased OPRM1 methylation in patients, independent of symptoms or pain sensitivity measures, supports the hypothesis of dysregulated opioidergic signaling in these conditions.
Source: Wyns A, Hendrix J, Van Campenhout J, Buntinx Y, Xiong H-Y, De Bruyne E, Godderis L, Nijs J, Rice D, Chiang D, et al. Hypermethylation of OPRM1: Deregulation of the Endogenous Opioid Pathway in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome and Fibromyalgia. International Journal of Molecular Sciences. 2026; 27(2):826. https://doi.org/10.3390/ijms27020826  https://www.mdpi.com/1422-0067/27/2/826 (Full text)

The Gut-Brain-Immune Axis in Environmental Sensitivity Illnesses: Microbiome-Centered Narrative Review of Fibromyalgia Syndrome, Myalgic Encephalomyelitis/Chronic Fatigue Syndrome, and Multiple Chemical Sensitivity

Abstract:

Environmental sensitivity illnesses-including fibromyalgia syndrome (FMS), myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS), and multiple chemical sensitivity (MCS)-are chronic, disabling disorders characterized by hypersensitivity to environmental stimuli, persistent fatigue, widespread pain, and neurocognitive and autonomic dysfunction. Although their diagnostic criteria differ, increasing evidence suggests overlapping clinical features and shared biological mechanisms. A unifying hypothesis highlights the gut-brain-immune axis, where alterations in the intestinal microbiome, epithelial barrier dysfunction, and aberrant immune signaling interact with central sensitization and systemic metabolic dysregulation.

Recent studies demonstrate reduced microbial diversity, depletion of anti-inflammatory taxa (e.g., Faecalibacterium prausnitzii, Bifidobacterium), and enrichment of pro-inflammatory Clostridium species across these conditions. These shifts likely alter production of short-chain fatty acids, amino acid metabolites, and complex lipids, with downstream effects on mitochondrial function, neuroinflammation, and host energy metabolism. Moreover, emerging clinical interventions-including probiotics, prebiotics, synbiotics, and fecal microbiota transplantation-suggest a potential role for microbiome-targeted therapies, though controlled evidence remains limited.

This review synthesizes current knowledge on microbiome alterations in FMS, ME/CFS, and MCS, emphasizing their convergence on metabolic and immune pathways. By integrating microbial, immunological, and neurophysiological perspectives, we propose a microbiome-centered framework for understanding environmental sensitivity illnesses and highlight avenues for translational research and therapeutic innovation.

Source: Watai K, Taniguchi M, Azuma K. The Gut-Brain-Immune Axis in Environmental Sensitivity Illnesses: Microbiome-Centered Narrative Review of Fibromyalgia Syndrome, Myalgic Encephalomyelitis/Chronic Fatigue Syndrome, and Multiple Chemical Sensitivity. Int J Mol Sci. 2025 Oct 14;26(20):9997. doi: 10.3390/ijms26209997. PMID: 41155291. https://www.mdpi.com/1422-0067/26/20/9997 (Full text)