All chronic illnesses - mental no less than physical - at the deepest level are an inflammatory response to an external object that has made an unwelcome entry inside the organism - broken through its protective shield - and disturbed its homeostasis. Entry of objects from one body system to another, like the intestinal bacterial flora entering into the peritoneum or blood stream, are reacted to as if they are an external object.
The inflammation is the organism's method of creating a wall around and extruding the unwelcome object out of the system and restore the earlier state. If the object cannot be expelled, excreted or exhaled then the organism works towards nullifying its harmful effects through embedding it and eventually making it a part of the organism, finding some 'secondary use' for it.
The process is assumed to happen just with physical objects that have traumatically entered into the organism, but the phenomena is equally applicable to the mind. Unpleasant experiences are treated as something foreign that should not be made part of the self (ego), and provoke mental (ego) defenses that try not to think about them any further, sometimes sealing them out of consciousness permanently by subjecting them to repression. They remain embedded in the unconscious memory banks, continuously subject to modification till they can be made part of one's self and 'secondary use' can be found for them.
These ego defenses are like the inflammatory response of the mind. Ego originates from the mental representation of body surface - eyes and ears being the most specialized parts of this body surface - and other body sensations including those that give report of one's muscular activities (kinesthetic sensations), and just like skin, and other body organs, heighten their activities to expel an unwanted foreign object at the physical level, ego mechanisms gear up their activities to nullify the harmful effects of mentally painful experiences. The id impulses - sexual and aggressive drives - that originate from inside the organism, if they cross a certain threshold and cannot be safely discharged without provoking a retaliation from the outside world, are treated as if they are arising from the outside and ego defenses are mobilized against them as if they are not part of oneself. An extreme example would be how a paranoid schizophrenic may enucleate his eyes to reject the scopophillic id impulses, treating the eyes not as part of one's body but as an alien evil force that is inimical to one's self.
Most interestingly an unpleasant psychosocial experience not only activates mental defenses, it simultaneously provokes the same somatic reactions that happens when some physical trauma occurs. This latter phenomena has far reaching consequences. It is as if the body has a tendency to sympathetically respond to any inflammatory activity anywhere and it does not matter whether the provocative agent is mental or physical. As if the organism anticipates that one traumatic event is likely to be followed by some more, and all defensive processes must be put on alert if there is stressful assault on any part of it.
The above idea which has been with me for a long time, and bits and pieces of which have appeared in my previous posts, found its impetus to be written in greater detail while listening to a patient of mine who commented that her throat was inflamed which means that her Crohn's (autoimmune inflammatory bowel disease) will follow suit in a few days. She claimed that any inflammatory reaction anywhere in her body becomes generalized and her intestines, because of previous vulnerabilities, show this sympathetic inflammatory response the most.
Inflammation is mobilization of body's counter-attack mechanisms to deal with anything unwanted from the outside. But when these counterattack mechanisms go beyond their call of duty and start overdoing their job then we get chronic diseases. The body's reaction to an external object should be commensurate to the strength of the trauma. If, however, the organism is genetically oversensitive and/or has been subjected to too many traumas in the past, the hatred/rejection of the outer world becomes so strong that response to any assault, no matter how minor, becomes pathologically disproportionate. Every unpleasant encounter with the outside gets under one's skin so to speak. All chronic diseases are kind of Post Traumatic Stress Disorder if one may be allowed to express the above idea in psychiatric parlance. In psychoanalytic terminology they are "Traumatic Neurosis": abreaction of stress through exaggerated (displaced) mental and somatic processes.
Now our body comes into contact with the external world via limited portals. Skin of course is phylogenetically the oldest organ, evolved to form a barrier between the subject and the object - between the self and the universe. Modifications of the skin occurred to create various portals to more efficiently imbibe aspects of the world essential to one's existence while keeping the unwanted objects at bay. The gastrointestinal tract evolved from the protoplasmic wall inlets that increased the cell (skin) surface to more effectively incorporate food and water and excrete the superfluous; the respiratory tract developed to provide infinitely greater oxygen and carbon dioxide exchange area in the lungs along with a long passageway to trap subtle pollutants in the nostril hair and block food particles at the larynx; the circulatory system became specialized for taking the nutrients and oxygen from GI and respiratory tracts to distant organs of the body and to bring excretions back to the same tracts and also to the renal-urinary system; the optic, nasal and oral passages for taking in visual, olfactory and gustatory impressions respectively; and finally the brain which is the most marvelous extension of the skin, and where impressions impinging upon the five senses are converted to complex perceptions - which are further refined into concepts (brain's 'shorthand') - to more quickly react to danger and to more expediently search for food and sexual objects.
Now with mental trauma if its effect cannot be countered by pure psychological means (ego defenses) the reaction spills into physical sphere - modeled after hysteria in which psychological conflicts and excitations are expressed through bodily innervations - and different body organs react as if they are dealing with an intrusion of an unwanted foreign physical object in their system.
A full appreciation of this phenomena forces us to correctly realize as to how most chronic diseases, even those that appear to be solidly somatic, are psychosomatic in nature, and are initiated and maintained by psychological traumas. Chronic somatic diseases are not so much a reaction to some physical insult as a result of psychological stresses that generate compulsions to rid the memory of the offensive person in displacement. In respiratory tract one finds that the spasms of bronchial muscles and asthmatic attack are motivated to symbolically choke the psychological irritant in the bronchial passage. In an analogous manner, in the upper GI tract, we pour excessive acid to burn the source of our stress and then regurgitate, after 'eating alive' the hated person, through the reverse peristalsis of Gastro-Esophageal Reflux Disease. The psychology of binging and purging may show itself to have its roots in the desire to ingest the ambivalently loved object (person) and then throwing him up as a hated (foreign) object. In lower GI tract we try to eliminate him through various forms of colitis; as if we want to 'bury him in excreta'. In urinary tract the desire to flush out the person who is 'pissing us off' is reflected in various forms of irritable bladder syndrome and interstitial cystitis. In eyes and surrounding paranasal sinuses inordinate amounts of mucosal secretions (post-nasal drip) occur as if to 'drown in tears' the person who is causing us the pain. In the circulatory system we gear up to deal with the hostile outside world by increasing our blood pressure, by mobilizing inappropriate amounts of sugar inside the cell to make it more readily available for instant energy in case we have to indulge in fight or flight, by gearing up various other components of metabolic syndrome like increasing the rate of oxidation and mobilizing various forms of immune mechanisms, the excessive activity of which leads to autoimmune disorders. In the skin lopsided production of dermal tissue, as if to 'make oneself thick skinned' against the sling and arrows of life, causes psoriasis, neurodermatitis and other skin blemishes. It may be mentioned that the suppurative skin reactions in which the unwanted intruder is embedded in a pocket of pus to be eventually spilled out, gives us in a most transparent fashion the raison d'etre of inflammatory reaction. Finally in the brain, the most important extension of skin, where perceptions correspond to the touch sensations of the skin and muscle (motor activities) of the body correspond to thought processes of all kinds, exaggerated perceptions (hysterical disturbances) and excessive thinking (obsessive disorders) occur when a person is subjected to a traumatically intruding outside world.
If I may be allowed to do so I may expand a little upon an interesting observation I have made upon GI tract's role in dealing with psychological irritants. Perhaps people's love for eating hot and spicy food and drinking harsh spirits - the latter's intoxicating/anesthetic effect act as an additional motive of course - may be a way to use the abrasive food as a symbol of the caustic world outside over which they can triumph by voluntarily swallowing its roughness. It is as if they are convincing themselves that no I am not subject to this hostile world against my wishes but it is I who is subjecting myself to this corrosiveness and enjoying it too. [It is not too different than how a woman who was sexually abused as a child repeatedly gets in to relationships with men who will repeat the sexual experience but over whom she has greater control now that she is an adult.] The human obsession with eating some food and not others, in Obsessional Neurosis and Autism reaching ridiculous proportions, is a way to reject the painful aspects of the outside world by symbolizing it in some foods. Thrill seekers and those who court other forms of troubles, their psychology is similar to those who eat highly seasoned food. They expose themselves to dangerous situations or lure worthless people into intimacy, those who are sure to harm them, so they can triumph over these unpleasant objects and purge them out of their system.
Finally in this context one may mention that pregnancy, which during my student days was an object of mirthful debate whether it should be looked upon as a physiological process or a disease - for it shows all the pathphysiological processes of an illness - can be conceptualized as an inflammatory response to a foreign irritant too. The man's spermatazoa is treated as an outside object, its impact is lessened by walling it off from rest of the organism with uterine muscles which are also used to extrude the final product, the baby, out of the system. Excessive cautionary fear of the woman towards the larger world may lead to infertility in her. Such an attitude is often present in highly narcissistic women who finds sex and its consequences at variance with their life trajectories. Such narcissism, where pregnancy and babies are looked upon as having no place in one's conception of ideal life, may pervade a culture to such an extent that the people belonging to it may slowly non-breed themselves in to extinction.