Imagine your body has a fire department. When the alarm sounds, the department mobilizes: adrenaline floods the system, inflammation rises, energy gets diverted from maintenance to emergency. This is correct and necessary. The body is supposed to do this.
Now imagine the alarm never stops. Not at full volume — just a low, constant sound. The fire department stays partially mobilized around the clock, year after year. At some point, the resources needed for maintenance — immune regulation, tissue repair, hormonal balance, gut health — start running short. The fire department has been using them. And the diseases that result from that long-term resource deficit look nothing like "trauma." They look like fibromyalgia. Chronic fatigue syndrome. Irritable bowel syndrome. Autoimmune disease. Migraine.
These are what Scaer calls the diseases of traumatic stress — not psychological sequelae, not coincidental comorbidities, but the physiological downstream of a threat-response system that was never told to stand down.1
Your body has a built-in chemical brake for the stress response. When the threat alarm fires, one of the things it eventually releases is cortisol — a hormone that does many jobs, but one of the most important is: it tells the immune system to calm down. It's the signal that says we're through the emergency, stand down.
Here's the counterintuitive part that matters clinically: people with acute PTSD — trauma in its early stages — have elevated cortisol. That makes sense. The alarm is running, cortisol is part of the response. But people with chronic PTSD — trauma that has been running for months or years — have LOW cortisol. Below normal.1
Why? Because the stress-response axis has been running so hard for so long that it has effectively burned out. The adrenal glands, which produce cortisol, have been responding to emergency signals so continuously that they've lost sensitivity to the trigger. The brake system is exhausted.
Now here's why this matters for physical disease: without adequate cortisol, the immune system doesn't get the "stand down" signal it needs. It stays activated. Chronic, low-grade inflammation persists without the normal checkpoint. And an immune system that's been running without a brake for long enough starts making mistakes — attacking the body's own tissue. This is the mechanism by which long-term PTSD predicts significantly higher rates of autoimmune disease: not metaphorically, not "stress weakens you," but through a specific hormonal cascade that removes the immune system's regulation signal.1
The gut is more wired into the stress system than most people realize. It has its own nervous system — sometimes called "the second brain" — and it is directly connected to the same threat-response network that runs your heart rate and blood pressure.
When the threat alarm fires, blood is redirected away from digestion and toward the muscles and heart. Gut motility changes. The lining of the intestines becomes more permeable. The immune cells embedded in the gut wall go on alert.
In a normal acute stressor, this resolves. In a chronically kindled threat-response system, it doesn't. The gut stays in emergency mode — motility irregular, permeability elevated, local immune cells chronically activated. The clinical result: irritable bowel syndrome, the pattern of cramping, unpredictable bowel function, and gut pain that has no structural explanation but is very real and very disruptive. In trauma populations, IBS rates are dramatically elevated — not because trauma survivors are anxious (though they may be) but because their gut's nerve supply is running the same chronic alarm as the rest of them.1
The conditions Scaer proposes belong to this category share a common profile: they appear in the years following trauma or extreme stress, they have no clean structural explanation, they resist standard treatment, and they frequently cluster in the same person.
Fibromyalgia — Widespread, migrating pain, tender points, exhaustion, and unrefreshing sleep. In the framework here: the threat-response system has sensitized pain-signaling pathways throughout the body (the kindled amygdala amplifies pain detection as part of hypervigilant threat monitoring), and the low-cortisol state allows inflammatory signaling to run without the normal brake.
Chronic Fatigue Syndrome (CFS) — Severe fatigue that doesn't improve with rest, "crashing" after even minimal exertion, brain fog, disrupted sleep. The cortisol-depleted stress axis can't mobilize energy on demand; the cardiovascular system, also regulated by the same threat-response network, doesn't respond normally to the demands of activity.
Reflex Sympathetic Dystrophy (RSD) — A regional pain syndrome with burning quality, skin changes, swelling, and altered temperature in a limb. In the somatic dissociation framework (see Somatic Dissociation), this is the most extreme expression of the regional autonomic disruption that trauma leaves in specific body areas.
Interstitial Cystitis — Bladder pain and urgency without infection. Pelvic trauma history is common in this population. The pelvic autonomic innervation is carrying the same regional activation that produces piriformis syndrome and pelvic floor dysfunction in other trauma survivors.
Migraine — The vascular instability of the stress-response system (blood vessels dilating and constricting erratically) combined with sensitized pain pathways creates the conditions for migraine, particularly in people whose threat-response system runs without consistent regulation.
Autoimmune disorders (rheumatoid arthritis, lupus, Hashimoto's, and others) — The low-cortisol state removes the immune brake; which specific autoimmune condition develops may depend on individual genetic vulnerabilities, but the shared mechanism — immune system running without its checkpoint — is proposed as common to the class.1
In 1941, Abraham Kardiner published observations about WWI veterans that should have changed medicine. He called the syndrome he was documenting "physioneurosis" — a neurological condition with both psychological and physical symptoms — and he described it with clinical precision: chronic autonomic hyperarousal, explosive startle responses, nightmares, avoidance, and an array of physical complaints including pain, fatigue, gastrointestinal disturbance, and cardiovascular irregularities.
He was right. He had accurate clinical observations and an appropriate neurophysiological framing. The medical establishment largely ignored him.1
Sixty years later, Scaer is describing the same syndrome with a richer vocabulary (kindling, amygdala, HPA axis, somatic dissociation) and more supporting science. The clinical picture is identical. This is not a case of science slowly building toward truth. This is a case of truth being discovered, filed away, and rediscovered multiple times — under "shell shock" after WWI, "combat fatigue" after WWII, "PTSD" after Vietnam, "complex PTSD" in the current era — while the medical establishment that should integrate it keeps finding reasons to treat the symptoms separately rather than recognize the pattern.
The Kardiner connection is not just historical curiosity. It is evidence of a sociological regularity: certain findings about trauma and the body get periodically uncovered and then institutionally misplaced, not because the evidence is poor but because the framework for interpreting evidence in medicine resists neurophysiological accounts of what have been classified as either "psychological" disorders or "medically unexplained" syndromes.
The standard psychiatric diagnosis for trauma, PTSD, was developed primarily from research on combat veterans and captures a specific profile: intrusive memories, avoidance of reminders, hyperarousal. This works reasonably well for a single traumatic event in an adult.
It doesn't work for the most common presentation of trauma-related physical disease: someone with a complicated childhood, years of chronic stress, a history of events that individually might not "qualify" as capital-T trauma, but whose accumulated impact on the nervous system has produced the kindling progression described in Kindling and Trauma Perpetuation. This person may not meet PTSD criteria at all — their intrusive symptoms and avoidance may be subtle or absent — but their fibromyalgia, their CFS, their autoimmune disease, their IBS are the story of what happened to them.
The alternative diagnostic frame Scaer points to is DESNOS — Disorders of Extreme Stress Not Otherwise Specified. DESNOS captures the broader range of what complex or developmental trauma does to a person: difficulty regulating emotions and impulses, altered states of consciousness, chronic shame and self-perception disturbances, difficulties in relationships, patterns of somatization, and disruptions in meaning-making. This is the clinical picture that maps onto the diseases of traumatic stress. A fibromyalgia patient assessed through the DESNOS lens looks different than one assessed through a rheumatology lens — and the treatment paths diverge accordingly.1
Scaer opens his book with a pointed historical note: the reason Western medicine struggles to integrate psychological cause with physical effect is usually attributed to Descartes — to a philosophical tradition of separating mind from body. The problem, Scaer notes, is that Descartes didn't actually argue for this separation. Descartes wrote that the soul and body are "intermingled" and cannot be cleanly separated. The philosophical framework that organized medicine toward treating "psychological" and "physical" as categorically distinct was not Descartes's — it was a misreading of Descartes that became institutionally entrenched.1
This claim requires verification against Descartes's primary text (The Passions of the Soul, 1649) before treating as established. [UNVERIFIED — check primary source]
Whether the historical attribution is correct or not, the practical consequence is visible: a patient presenting with fibromyalgia, CFS, and IBS will be routed to three different specialists who treat their respective organ systems. None of them will ask: What were you going through in the five years before all of this started? The diagnostic architecture doesn't have a place for that question. And so the answer — which might point toward the single mechanism producing all three conditions — is never obtained.
Kardiner and Scaer agree on the clinical picture and the neurophysiological framing — across a 60-year gap and without either having access to the other's supporting science. That cross-temporal convergence is one of the stronger pieces of evidence that both are describing a real phenomenon, not an artifact of one researcher's clinical context.
The tension between Scaer's framework and standard biomedical research is about what counts as evidence. Scaer's argument is mechanistically sound — the hormonal and immunological pathways he describes are real and documented. But the specific causal claims (that this patient's fibromyalgia is a kindling disease, that this autoimmune condition is downstream of trauma-driven cortisol depletion) require prospective epidemiological research that didn't exist at the time of writing and remains incomplete. The mechanism is plausible; the disease-level causal attribution, for specific patients, is a clinical extrapolation. [PRACTITIONER — synthesis and clinical observation; specific disease-etiology claims require prospective corroboration]
The plain connection: "medically unexplained" is a category produced by a diagnostic system that can't see the cause — not because the cause doesn't exist but because it lives in a different disciplinary territory than the symptom.
History: The Kardiner erasure — 1941 to 2001, the same clinical reality rediscovered twice — is a case study in how institutions handle findings that cut across disciplinary boundaries. What gets erased is not the data (Kardiner's observations were documented and published) but the framing that would make the data actionable. The history of trauma medicine is not a story of science advancing toward truth. It is a story of truth being repeatedly documented, filed into a category the institution can't metabolize, and rediscovered by the next clinician willing to look. This pattern suggests that integrating Scaer's framework will require institutional change, not just evidence accumulation — the evidence has been there since at least 1941.
Eastern Spirituality: Karmas and Samskaras — Ayurvedic medicine proposes that unresolved samskaras accumulate in the system and eventually produce physical disease — a progression from subtle imbalance (vikruti) to manifest illness (roga). Ayurvedic treatment protocols (panchakarma, herbal medicine, dietary intervention, breathing practices) are specifically designed to address the samskara-disease interface. The structural parallel to Scaer's kindling-to-disease trajectory is precise: both describe a pathway from unresolved activation → systemic dysregulation → tissue expression. The clinical difference is that Ayurveda has developed detailed intervention protocols at precisely the point where Scaer's framework runs thin. The ancient medical tradition may be more operationally useful at the "what to do" level than the modern neurophysiological account that explains why.
The Sharpest Implication Every fibromyalgia patient cycling through specialists, every CFS patient told their fatigue is psychosomatic, every autoimmune patient who can't understand why this happened to them — a meaningful subset of these people have a trauma story that precedes the illness onset, and no one has connected those dots because the diagnostic architecture has no pathway that crosses the boundary between "trauma" (psychiatry's territory) and "unexplained somatic disease" (medicine's territory). The intervention isn't to turn every rheumatologist into a trauma therapist. It's to add a single protocol question at initial workup for these conditions: What were the two or three years before this started like for you? The answer would redirect a significant proportion of these cases toward an understanding of their illness that they have never received.
Generative Questions