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In 1968 Ronald Melzack and Kenneth Casey re-imagined pain as more than just a sensation,[1] and this conceptual model now underpins all thinking in modern pain psychology and pain neuroscience. They described three dimensions of pain:
- sensory-discriminative: sense of the quality,[2] location, duration and intensity of the pain
- affective-motivational: unpleasantness and urge to escape the unpleasantness
- cognitive-evaluative: cognitions such as appraisal, cultural values, distraction and hypnotic suggestion.
Personally, I would add a fourth: the social dimension of pain. But this isn't the place to elaborate on that.
Here I discuss the affective-motivational dimension, the unpleasantness.
Unpleasantness is also called "suffering", "discomfort", "torment", "hurt", "negative affect", "negative valence", "negative hedonic tone", "aversiveness" and "distress". I'll use "suffering" here.[3]
Suffering is found in three classes of feelings:
1. It is a dimension of unpleasant homeostatic feelings like hunger, fatigue and hyperthermia. Unpleasant homeostatic feelings torment us with suffering until we satisfy them with specific behaviour aimed at maintaining the body in its ideal state. (In hunger: eating, in fatigue: resting, and in hyperthermia: stepping into the shade.)

Pain is an unpleasant homeostatic feeling; we respond to it by withdrawing from a harmful situation, protecting a damaged body part while it heals, and avoiding similar experiences in the future.
2. Suffering also plays a role in negative emotions like grief, anger and fear, and negative moods like misery, irritability and anxiety.
3. And it is an essential part of some social feelings (e.g., empathy, rejection, shame, loneliness).
Suffering likely evolved first and was enlisted by homeostatic feelings, emotions and social feelings as they emerged later in animal evolution.[4]
It is likely that just one neural network generates suffering, and every unpleasant feeling employs this one suffering network.[5]
What does suffering do to us?
I am studying the effect of suffering on human emotion, cognition and social engagement and I have focussed on three causes of suffering — hunger, sleep deprivation and pain — because each of these has a body of scholarship addressing, to some extent, its affective, cognitive and social impacts.
I have more reading to do but it is looking like each of these distressing homeostatic feelings generates in humans the same set of clinically significant symptoms:
- Increased frequency, intensity and duration of negative mood states (e.g., wretchedness, anxiety, irritability) and negative emotional events (e.g., grief, fear, anger), and heightened affective response to negative stimuli (neuroticism): things that hurt, hurt more.[6]
- Slowed mental processing speed, reduced working memory capacity and impaired attention control, impulse inhibition and emotion regulation.
- Impaired social feeling and reduced social engagement.
Until someone finds an instance of suffering that does not cause this cluster of symptoms, I shall assume all suffering, regardless of its cause, produces this syndrome.
This syndrome is found and is a major contributor to disability in all instances of distressing functional mental disorder.
Some functional mental disorders don't necessarily come with suffering/distress. Certain tic disorders and personality disorders, for example, only qualify as mental illness because they may interfere with the person's functioning, but not necessarily with their happiness. This cluster of affective, cognitive and social symptoms I call the suffering syndrome is not usually or necessarily found in these non-distressing disorders but it is a feature of all distressing functional mental illnesses.
Look, for example, at the extract below from the "associated features" of schizophrenia (a mental disorder strongly associated with distress) in DSM-5-TR. Compare the symptoms I have underlined in that text with the symptoms of suffering listed in the bullet points above.
All the symptoms of the distress syndrome, except exaggerated affective response, are found in the DSM associated features of schizophrenia.
Individuals with schizophrenia may display inappropriate affect (e.g., laughing in the absense of an appropriate stimulus); a dysphoric mood that can take the form of depression, anxiety or anger; a disturbed sleep pattern (e.g., daytime sleeping and nighttime activity); and a lack of interest in eating or food refusal. Depersonalization, derealization and somatic concerns may occur and sometimes reach delusional proportions. Anxieties and phobias are common. Cognitive deficits in schizophrenia are common and are strongly linked to vocational and functional impairments. These deficits can include decrements in declaritive memory, working memory, language function, and other executive functions, as well as slower processing speed. Abnormalities in sensory processing and inhibitory capacity as well as reductions in attention are also found. Some individuals with schizophrenia show social cognition deficits, including deficits in the ability to infer the intentions of other people (theory of mind).
Eugen Bleuler in 1911 addressed exaggerated affective response in his unmedicated schizophrenic patients:
Particularly in the beginning of their illness, these patients quite consciously shun any contact with reality because their affects are so powerful that they must avoid everything which might arouse their emotions. The apathy toward the outer world is, then, a secondary one springing from hypertrophied sensitivity." (p. 65)[7]
Now, think for a moment about the distressing mental illness you are most familiar with. Do you see mental processing speed, working memory or attention problems? Problems with emotion regulation or impulse inhibition? Depression, anxiety and/or irritability? Problems with social sensitivity or social engagement? Affective hyper-reactivity (or affective disengagement like Bleuler's schizophrenic patients)?
Again, for emphasis, every mental illness that features distress features this syndrome.
What is distress/suffering doing in functional mental illness? What is its role?
Recently, a historian of psychiatry told me, "Suffering is central to serious mental illness. Whether it is the cause or the effect, or something of both, is an open question."
I'm sure it is an open question in his mind but the causal relationship between mental disorder and distress is not an open question in psychiatry.
In psychiatry, at least in its bible the DSM, it is always the symptoms of mental disorder that cause distress, never distress that causes the symptoms of mental disorder.
Look at this from DSM-5-TR's diagnostic criteria for major depressive disorder:
The symptoms cause clinically significant distress or impairment in social, occupational, or other important areas of functioning
This formulation occurs throughout DSM-5-TR,[8] and it has been a feature of the DSM since its third edition in 1980 when the lead author laid down new essential criteria for every diagnosis, including: the symptoms must be distressing to the individual or the symptoms must impair the individual's ability to function.
I believe distress, in mental disorder, is causing the same devastating set of symptoms it causes in hunger, sleep deprivation and pain, and psychiatry, if it wants to heal this significant set of cognitive, affective and social impairments common to all distressing functional mental disorders, should search out all sources of the patient's distress. Don't ignore distressing homeostatic conditions such as insulin resistance, hormone imbalances, vitamin or mineral deficiencies or excesses, inflammation, infection, etc..
But the diverse cluster of cognitive, affective and social symptoms that comprise the distress syndrome are not the only features of distressing mental illness. What about the symptoms that distinguish one DSM entity from another — mania, delusions, hallucinations, obsessions, etc.?
Well, they may be summoned by distress from a propensity in the patient's biological inheritance, modified by life experience and social state (diathesis-stress, an old idea[9]), so, eliminating ongoing or recurring distress may at least to some degree ameliorate these eccentricities, while resolving the seriously disabling affective, cognitive and social harms of suffering.
"Some researchers [claim] that a single dimension—similar to the g factor in intelligence, that provides a summary measure of general mental ability—accounts for all types of psychopathology accross the lifecourse. 'Today's patient with schizophrenia was yesterday's boy with conduct disorder or girl with social phobia and tomorrow's elderly person with severe depression', psychologists Avshalom Caspi and Terry E. Moffitt assert." — Allan V. Horowitz, DSM: A history of psychiatry's bible (2021), chapter 6.
Caspi's and Moffitt's proposal is in this 2018 American Journal of Psychiatry article. They discuss "the new idea that there may be one underlying factor that summarizes individuals’ propensity to develop any and all forms of common psychopathologies," which they call p.
This p factor is, of course, suffering.
Notes and citations
edit- ↑ Melzack, Ronald; Casey, Kenneth (1968). "Sensory, Motivational, and Central Control Determinants of Pain". In Kenshalo, Dan (ed.). The Skin Senses. Springfield, Illinois: Charles C Thomas. p. 432.
- ↑ "Quality" in pain science means the unique sensation that distinguishes pain from other feelings like itch, nausea and thirst, or the characteristic that distinguishes one pain from another, e.g., tingling pain vs. burning pain.
- ↑ In 1988, Wade, Price et al. tried to establish a linguistic convention: they proposed using "unpleasantness" for the negative affect that is usually a dimension of pain, described by Melzack and Casey above, and "suffering" for the negative affect attending thoughts and emotions that are consequent to pain.
They defined "a second stage of pain-related affect that can be conceptualized generally as 'suffering'. [...] It is composed of evaluations and beliefs [...] and consequently of negative emotions related to these evaluative components (such as depression, fear, anxiety, anger, frustration)."
I'm not aware of widespread adoption of this convention and I don't make their proposed distinction here. For the present, I treat "negative affect", "unpleasantness", "suffering", "distress" and all the other terms listed above as synonyms.
Cited in: Gatchel, Robert J.; Weisberg, James N., eds. (2000). Personality characteristics of patients with pain. Washington, DC: American Psychological Association. p. 89. ISBN 978-1-55798-646-7. - ↑ Antonio Damasio in his 2021 book, Feeling and Knowing, puts the appearance of basic discomfort and wellbeing before the emergence of homeostatic feelings in evolution.
- ↑ Damasio, ibid, says, "But we often overlook the fact that our psychological and sociocultural situations also gain access to the machinery of homeostasis in such a way that they too result in pain or pleasure, malaise or well-being. In its unerring push for economy, nature did not bother to create new devices to handle the goodness or badness of our personal psychology or social condition." P.127.
- ↑ This idea, that ongoing suffering makes novel instances of suffering more unpleasant, does not clash with the idea of diffuse noxious inhibitory control (DNIC), where the presence of one pain may reduce the intensity of another when both are being experienced at the same time. DNIC involves sensation intensity. Neuroticism involves suffering intensity. Sensation and suffering are two distinct concepts and they engage two different neural networks.
Also, neuroticism is not the same as central sensitization, where ongoing pain may increase our likelihood of experiencing pain from a novel noxious stimulus, or increase the intensity of novel pain. Central sensitization is, like DNIC, a feature of the sensory-discriminative system, neuroticism is a feature of the suffering system. - ↑ Bleuler, Eugen (1911). Dementia Praecox. Translated by Joseph Zinkin in 1950. New York: International Universities Press.
{{cite book}}: CS1 maint: numeric names: translators list (link) - ↑ From page 23 of DSM-5-TR: "In the absence of clear biological markers or clinically useful measurements of severity for many mental disorders, it has not been possible to completely separate normal from pathological symptom expressions contained in diagnostic criteria. This gap in information is particularly problematic in clinical situations in which the individual's symptom presentation by itself (particularly in mild forms) is not inherently pathological and may be encountered in those for whom a diagnosis of 'mental disorder' would be inappropriate. Therefore, a generic diagnostic criterion requiring distress or disability has been used to establish disorder thresholds, usually worded 'the disturbance causes clinically significant distress or impairment in social, occupational, or other important areas of functioning.'"
- ↑ Kendler, Kenneth S. (July 2020). "A Prehistory of the Diathesis-Stress Model: Predisposing and Exciting Causes of Insanity in the 19th Century". American Journal of Psychiatry. 177 (7): 576–588. doi:10.1176/appi.ajp.2020.19111213. ISSN 0002-953X.