The first thing you have to understand about Bob Heath is his charisma. If you were casting a movie and looking for someone to play the scientist-hero, he would be the first and last name on your list. In every profile, every interview, the topic of his presence came up: he was Gary Cooper or Cary Grant or Gregory Peck in a crisp white lab coat. “He looked like a god – and carried himself like one,” says his former colleague Marilyn Skinner.

The second thing is that he was talented – perhaps too talented. He was board-certified in both psychiatry and neurology. He was a qualified psychoanalyst. He could treat a patient, diagnose a mental illness, read an EEG and dash off a paper, all before heading off to the country club for a round of golf.

The third thing is that the one true love of his life wasn’t a woman, but an area of the brain. Imagine a line that goes through one ear and out the other. Now take another line that runs dead centre from the top of your skull and down through your tongue. Where the two meet is what Heath labelled the septal area, although scientists today would probably call it the nucleus accumbens. For Heath, it was the seat of pleasure and emotions that he thought would allow him to unlock the human brain.

Born in 1915 in Pittsburgh, Heath trained as a neurologist, before being drafted into service as a military psychiatrist in World War II. He rapidly aligned himself with the new breed of biological psychiatrists – scientists who argued that what were traditionally thought of as diseases of the mind were often actually diseases of the brain and could therefore be cured through surgery, not therapy.

There was already some obvious evidence for this, in the shape of the way that patients’ behaviour changed after prefrontal lobotomy. This was the most widespread form of what was known as psychosurgery – the surgical treatment of mental illness. Yet even though the procedure, which involved chopping away the connections to much of the brain’s frontal lobe, was growing in popularity, Heath and his colleagues at Columbia University rightly viewed it as crude and ineffective. They decided to compare it with a much less invasive alternative, which they called topectomy: this involved targeting and removing specific areas of the cortex, in order to avoid wider damage to the brain.

© Michael Bodiam and Anna Lomax

Heath had already developed a particular interest in schizophrenia, which he viewed as the single greatest challenge in mental health, affecting roughly 2 per cent of Americans. He noticed that such patients seemed largely unaffected by either lobotomy or topectomy; since these procedures targeted only the most immediately accessible part of the brain, the cortex, he concluded that their symptoms must be more deep-rooted.

So Heath began his investigations of the subcortex (literally, ‘the part below the surface’). And one particular area – the septal region – appeared particularly promising. When it was damaged or destroyed in cats and monkeys, they started behaving in a startlingly similar fashion to people with schizophrenia: their emotions were dulled, they lost their ability to experience pleasure (a phenomenon known as anhedonia), and they generally seemed to be removed from reality.

This reinforced Heath’s burgeoning conviction that schizophrenia was a biological, not a psychological, problem: something “dependent upon a defect in basic machinery, rather than a complication of environment”, as he would later write. By implanting electrodes into the deepest parts of the brain, he could not only examine how this machinery operated, but also – he hoped – jolt it back into life.

There was just one problem. Heath could – and did – carry out all the tests he wanted on animals, but he couldn’t test his theories on humans: not so much for ethical reasons as because his colleagues at Columbia weren’t interested in the subcortex. Then, on a trip to Atlantic City, he found himself lying on the beach next to a man from New Orleans. He was the dean of Tulane University’s medical school, and he was looking to set up a psychiatry department. He’d heard good things about a guy called Bob Heath. I’m Bob Heath, said Bob Heath. And so they started to talk.

© Michael Bodiam and Anna Lomax

For the 35-year-old, the job at Tulane was an irresistible opportunity. New Orleans was an academic backwater. But it had something very special: in the words of his future colleague Arthur Epstein, “a big sprawling beautiful hospital, containing some of the sickest patients you will ever see”.

This was Charity Hospital, a vast, brutalist 1930s edifice through which the poor and sick of New Orleans flowed in their thousands. Heath was open about the fact that it was this endless supply of potential patients – or, as he put it, the “tremendous amount of clinical material” – that attracted him to the job, because it gave him the chance to realise his outsize ambitions. He moved to New Orleans in 1949: within a year, he had persuaded Charity’s governors to budget up to $400,000 to set up a 150-bed psychiatric unit on the third floor, which would enable him to tackle a waiting list for psychosurgery that was already ten months long.

Heath’s new position made him one of the most powerful men in the Louisiana mental health system. As well as Charity, he held positions at other New Orleans hospitals such as DePaul, Touro and the Veterans Administration Center, and later Tulane’s own private hospital. He maintained an experimental unit – at the state’s expense – at the East Louisiana Mental Hospital in Jackson, and was involved with another facility in Mandeville. If he needed healthy volunteers, he had free access to inmates at the state prison complex at Angola.

On top of this, there was his role within Tulane. Uniquely, his new department combined not just neurology and psychiatry – itself a reflection of his then-radical commitment to treating the mind and brain as linked – but also a psychoanalytic institute modelled on the work of his mentor Sandor Rado, who had argued for the key role of pleasure in motivating behaviour: Heath urged all of his colleagues to learn analysis, and to be analysed themselves. By 1970, the time of the ‘gay cure’ experiment, there were almost 200 staff and medical students under his supervision.