Epicurianism
Epicurus argues that hedonism is sustainable with prudence, that is, if one can acquire and possess the ability to govern action by the use of reason:
https://core.ac.uk/download/pdf/213401298.pdf
Epicurus (341–270 BCE) was a Hellenistic
Greek moral philosopher who identified the
goal of life as happiness.
For Epicurus, philosophy was above all
therapeutic. Philodemos records the
tetrapharmakos (“the fourfold cure”), which
encapsulated the essentials of the Epicurean
outlook as follows: “God is not to be feared,
death should cause no anxiety, easily obtained
is the good, and easily endured is the bad”
(Herculaneum Papyrus 1005).
William James
James wrote The Varieties of Religious Experience. The excellent article below quotes extensively from this source on the subject matter of The Healthy-Minded & Sick Souls:
https://philosophicalsociety.com/Archives/The%20Healthy-Minded%20&%20Sick%20Soul.htm
William James observes that individuals, by degrees, can be characterized as healthy-minded or as morbid-minded. In summary, the healthy-minded seem to actively repel suffering and the problem of evil; the sick souls are unable to actively repel suffering or the problem of evil. James also gives examples of conversions or counter-conversions between these two modes: mental happiness or mental suffering.
Sigmund Freud
Freud abstracts away from the social domain of self and others to describe the cognitive functions of the biological ego. I summarize the ego, for brevity, as the effort to govern action in the sensory context. In Civilization and It's Discontents (perhaps translated somewhat poorly into English), Freud says the ego is born with a biological drive to live and to become happy and to remain so in the world. He calls this the Eros drive. Freud argues that the sensory context of the ego is driven by three joint operating causes: by an inner source of biological impulses, by the ego itself, and by external reality. In this context the body is a source of eventual disability, disease, and death, so the ego is threatened by internal enemies to its persistent happiness. The external parents, peers, and social institutions can aid or impair the ego in its effort to live and become happy in the world, so social interactions are a source of happiness or suffering. Natural reality can destroy the ego from outside and the only remedy against hostile internal or external forces is the ego itself or the relations the ego forms with other humans expressing their ego. Freud argues that psychoanalysis or other social institutions can help the suffering ego adjust to natural and social reality, and this orientation toward reality will produce a mix of happiness and suffering for the typical individual. I would conclude that Freud regards persistent happiness as unsustainable in the long term because the conscious ego is under potential threat from hostile internal or external forces.
Freud - Hedonic Treadmill
Sigmund Freud, again in Civilization and It's Discontents, said something about the concept called the hedonic treadmill. I am using my recall of the concept not his exact words. Freud wrote that if the ego takes action to intensify pleasure, then this will often yield intense pleasure, but further persistence in the activity will not persist the intensity of pleasure, which naturally tends to fade. Then the ego would have to switch to another activity to intensify pleasure at least in the short run. In other words, persistent pleasure is sustained by switching activities and the most intense pleasures are not persistent for very long periods of time.
Baruch Spinoza
Baruch Spinoza describes an emotion (affect) as a feeling of desire, pleasure, or pain accompanied by an idea of its cause. He describes desire as appetite accompanied by consciousness thereof. This means appetite is an unconscious source of cause of desire. Also, if the body desires to feel persistent pleasure (happiness) and avoid persistent pain (suffering) then it has an unconscious appetite generating our conscious discussions of hedonism. Helmholtz describes aspects of the sensory context as the product of a neurological-cognitive process that he describes as unconscious inference. The feelings and causal ideas are conscious attributes of the sensory context.
Hedonism is sustainable in this context if the body and/or conscious self can accurately form ideas about the causes of pleasure and pain and act to persist pleasure and eliminate pain. Admittedly this reduction model is too simplified; but the model may be used to propose reasons for the problem of suffering and evil.
Thomas Szasz
Thomas Szasz wrote the controversial book The Myth of Mental Illness. Szasz argues, in this book, that a person complains when they feel pain. In terms of professions and patterns of social drama the person can: (1) complain to the medical doctor; (2) complain to social workers or justice workers; and (3) complain to the psychiatrist or psychologist.
Medical doctors hear complaints and look for signs and symptoms of disease or disability. The diagnosis of medical disability or disease does not depend on the character, personality, or behavior patterns of the patient. The job of the doctor is to identify a cause of disease or disability, and, when possible, provide a remedy.
Social workers or justice workers hear complaints and look for social patterns of adverse present living conditions. The cause of suffering or persistent pain is a social condition and the potential remedy is to alter the social condition.
Psychiatrists are medical doctors who can help other doctors identify, and perhaps rule out, the existence of medical disability or disease in a particular case. If one also rules out existing social conditions as a legitimate cause for complaint, then what remains is some form of residual pain or persistent pain in the patient (suffering person).
Szasz argues that mental illness is a category error because the diagnosis of a mental disorder involves only two things: (1) a pattern of behavior; and (2) an interpretation of what it means. This has more in common with religious judgments and judicial reasoning than with the practice of medicine.
Szasz observes that when the child is young the complaints are made to the parents. Therefore dramatic patterns in the professions can be seen as reenactments of the pattern of parent-child interaction but with the further meaning of the adult patient-expert interaction as part of the drama. In this context suffering and the effort to find a remedy evoke the incorporation of dramatic roles and residual childhood memories. I do not recall Szasz making extensive discussion of aesthetic pleasure or pain. But it is evident to me, in part via reading Szasz, that aesthetic emotions at times are the primary if not exclusive driver of social drama.
Hugh Gibbons
Hugh Gibbons, my professor of legal philosophy in 1991, wrote several papers or short books on the justification of law and/or the biological basis of law:
http://www.biologyoflaw.org/Downloads/index.htm
Hugh once describe actionable harm versus aesthetic harm as follows. If the plantiff feels a spiritual connection to all life, then observes me trimming my hedges, and has a nervous breakdown, then am I liable for causing harm under the law? The answer is no because the law only hears a claim for actionable harm. The aesthetic suffering of persons who fall outside the typical norms of society is not an actionable harm to the will of another under the law.