The Hungarian-American psychiatrist and writer Thomas Szasz, who has died aged 92, was regarded by many as the leading 20th- and 21st-century moral philosopher of psychiatry and psychotherapy. Others saw him as a dangerous and seductive influence, advocating neglect of some of society's most helpless members.
Szasz had a deep faith in human freedom. Human beings, he said, are free agents, fully responsible for their actions. He denounced any incursions on civil liberties in the name of psychiatry. To some people, Szasz appeared almost frivolously to ignore the obvious anguish and incapacity of many. But he told me that not a week went by without his hearing from desperate patients that he was the only person who understood their predicament.
In the best known of his 36 books, The Myth of Mental Illness (1961), Szasz argued that mental health and mental illness are alienated, pseudo-scientific, pseudo-medical terms, and for the next half-century he insisted that illness, in the modern, scientific sense, applies only to bodies, not to minds – except as a metaphor. A bodily organ, the heart, can be diseased, but to be heartsick or homesick, though real enough, is not to be medically, but only metaphorically, ill. Equally metaphorical, said Szasz, were such supposed mental illnesses as hysteria, obsessional neurosis, schizophrenia and depression.
He defended an individual's right to give informed consent to treatment, such as drugs, electroconvulsive therapy or even destructive psycho-surgery. But he pointed out that even if this made the individual feel better, it did not prove that he or she had been ill. If someone diagnosed as mentally ill should turn out to have a brain disease, then this would be a genuine physical illness, not a metaphorical mental one, and should be treated by neurologists, not psychiatrists.
Szasz's primary concern was the use of the metaphor of mental illness to give false legitimacy to compulsory psychiatry – coercing the innocent – and the insanity defence – excusing the guilty. He denounced these complementary uses of psychiatry as a crime against humanity and called for them to be legally abolished.
His opponents said that he was so obsessed with abstract justice, freedom and responsibility that he denied the medical problems of suffering patients whose mental illnesses made them unable to take responsibility. But Szasz was deeply concerned with human suffering. His point was simply that suffering was not necessarily a medical problem, did not imply lack of responsibility and should not be treated forcibly.
However, it is not generally realised how committed he was to voluntary psychotherapy. At a seminar in 2007 he said: "Psychotherapy is one of the most worthwhile things in the world." Although, in The Myth of Psychotherapy (1978), he wrote that Freud had misdescribed psychotherapy as a science and medical treatment, Szasz revered the possibility Freud had opened up, of searching conversation between consenting adults.
He saw compulsory psychiatry, no matter how compassionately intended, as patronising and infantilising. Many observers have found that his description of the ever-increasing medicalisation of many human situations – what he termed the "therapeutic state" – remains uncannily accurate.
Born in Budapest, Szasz was the son of a Jewish businessman, Julius, and his wife, Lily. His preoccupation with liberty began when, as a boy of six, he was forced to go to school. On long walks, he was shown prisons, hospitals – and psychiatric hospitals, which he thought, even as a child, should also be called prisons. By adolescence, he found that "inquiring into the justification for locking up mad people is taboo. Crazy people belong in madhouses. Only a crazy person would ask, why?" He thought, even then, that mental illness was not an illness. He never had to give up a belief in mental illness, since he had never had such a belief.
By 1938, Hungary had sided with Nazi Germany, and the family moved to Cincinnati, Ohio. At the university there, Szasz graduated in physics in 1941 and medicine in 1944. He trained at the Chicago Institute for Psychoanalysis, gaining his diploma in 1950, and then worked on its staff for five years from 1951, undertaking military service at the US naval hospital, Bethesda, Maryland, during the last two. He told me that he "felt viscerally upset" by "the dehumanised language of psychiatry and psychoanalysis", but made sure that he never had to treat an involuntary patient.
Then he settled at the Upstate Medical Centre of the State University of New York, in Syracuse, as professor of psychiatry, becoming emeritus in 1990. He did not publish his heretical ideas on mental illness until he had obtained tenure. He taught psychiatry, he said, as an atheist might teach theology.
Szasz was an atheist, but he said his atheism was "religious". He called human beings ineffable, in the sense that they could not be ultimately described by a system or a science. Psychotherapy was likewise ineffable – a secular form of the "cure of souls". Psychotherapists were more like rabbis or priests than like medical doctors. This required absolute confidentiality, as in the confessional. It was no business of third parties or the state.
His last book, Suicide Prohibition: The Shame of Medicine (2011), was a protest against suicide prevention, the primary justification for compulsory psychiatry. However, he was equally opposed to physician-assisted suicide, which he saw as yet another intrusion of medicine into living and dying.
To his supporters, Szasz was a great existential and libertarian thinker who explored the consequences of a commitment to personal responsibility and freedom in many fields. Others acknowledged his critical stand against what they called abuses of psychiatry, but rejected his view that compulsory psychiatry is itself an abuse. They argued that mental illness is indeed illness and may justify compulsion, and that Szasz was irresponsible in denying this.
He was controversial to the end. In Szasz Under Fire: The Psychiatric Abolitionist Faces His Critics (2004), edited by Jeffrey Schaler, his views were challenged from various angles by leading psychiatrists and philosophers, and defended meticulously by Szasz himself.
Szasz was a courteous listener and greatly enjoyed dialogue. He preferred it to lecturing, though he was a brilliant speaker. He published 11 books after turning 80, and conducted an electrifying all-day seminar in London at 90. He had great personal warmth.
Szasz's wife, Rosine, died in 1971. He is survived by his daughters, Margot and Suzy, by his grandson, Andrew, and by his older brother, George.
• Thomas Stephen Szasz, psychiatrist and writer, born 15 April 1920; died 8 September 2012
