In 1926, Graham Greene was summoned by his doctor to alert him to a serious condition that carried certain risks that he must “consider carefully before marriage”. The diagnosis had already been given to his parents some months earlier, after Greene suffered a bout of fainting, but it had been agreed that the secret was best kept from their son; that he “ought not to be told what the matter is in any terms that included the word epilepsy”.

Writing in his autobiography, A Sort of Life, Greene recalled that at that time epilepsy ranked alongside cancer and leprosy as the condition most feared by the British public. Even though his physician held out the hope that his epileptic episodes might be arrested by “good walks and Kepler’s Malt Extract”, the 22-year-old writer was devastated. He’d recently pledged himself to be married, but now he was being counselled about the risks of fatherhood as epilepsy could be inherited. The next day he found himself “standing on an underground platform … trying to summon the will and courage to jump”.

Ancient Romans believed that sex might prevent epilepsy, but other cultures before and after contended that the opposite was true. In England the prevailing view of epilepsy and marriage had not much changed from when the Victorian physician Sir Edward Sieveking wrote in his study On Epilepsy in 1858, “The marital act itself may become an exciting cause of epilepsy, and as we know the hereditary influence of the disease is great, we ought not to counsel epileptics to marry.”

Greene confided that in contemplating suicide, he was exhausted “by the thought of starting a completely different future” from the one he’d imagined for himself. Luckily, for some people with epilepsy, their seizures are finite: they come to an end without medical intervention. But although Greene would have no further fainting attacks, he had been given a significant jolt.

In Britain up until 1970, a marriage could be annulled if “either party was, at the time of marriage, of unsound mind, mentally defective or subject to recurrent fits of insanity or epilepsy”. That law was repealed in Britain in 1971, and the year earlier in Finland, but comparable legislation was still being enforced around the globe.

Facebook Twitter Pinterest Graham Greene recalled how epilepsy ranked alongside leprosy as the condition most feared by the public. Photograph: Tony McGrath/The Observer

Epilepsy is considered by the courts of numerous countries including Kenya, Jamaica and Nigeria to be grounds for a decree of nullity of marriage. And it is still the subject of legal challenges in many parts of the world, most notably India. Under the Hindu Marriage Act of 1955, a wedding could only be solemnised “if at the time of marriage neither party suffers from recurrent attacks of insanity or epilepsy”. Though this proviso was amended in 1999 so that the words “or epilepsy” were omitted, plaintiffs regularly petition the courts for divorce on matrimonial grounds of “unsoundness of mind” or “epileptic insanity”.

Epilepsy has been wedded to numerous epithets, such as “degenerate”, “lunatic” and “feeble-minded”. When Prince John, the son of George V, developed epilepsy, he was taken away to Sandringham and never mentioned again.

Until 1970, a marriage could be annulled in Britain if either party was subject to fits of epilepsy

Stung by the stigma, unsurprisingly, people with epilepsy did not disclose that they suffered from the condition. The 19th-century writer and illustrator Edward Lear kept a diary for all of his adult life. He was fastidious, rarely going a day without making an entry. The diaries are frank. He even made a note of his bowel movements. Yet there is one aspect of his life that was never recorded. Looking through the diaries you occasionally come across an entry that includes the letter “X”. These were the days on which Lear had epileptic seizures.

Occasionally he referred to his condition as “the Demon” and, looking back over his life, Lear accepted phlegmatically that the Demon’s constant presence from a young age “would have prevented happiness under any sort of circumstances. It is a most merciful blessing that I have kept up as I have, and have not gone utterly to the bad mad sad.”

Lear had had his first attack as a five-year-old child, but no one outside his family knew of his condition or the shame he felt about it. His reticence would have been appreciated by the poet Emily Dickinson, who was ill for much of her 55 years. The sparse medical notes do not lead to a definitive diagnosis, but a close analysis of her work suggests to biographers such as Lyndall Gordon that the “It” at the centre of a number of Dickinson’s poems is epilepsy. Further clues to the “loaded gun” perpetually aimed at the poet and the internal volcanic explosions that threatened to disrupt her life are offered by lines such as “I felt a cleaving in my mind – / As if my Brain had split –”.

If the “It” is both deficit and credit then that’s because though the paroxysms constrained her, and led to her exile from society as a hermitic recluse in Amherst, they were also the source material of alchemical poetic experiments. But why the secrecy? For many years after her death (and before) the narrative that explained Dickinson’s seclusion was that she was a quaint young woman disappointed in love who sought refuge from that humiliation in her father’s house. But the imagery in many of her poems, the repeated anxiety expressed over a loss of decorum and control, together with the pharmacological records of the prescriptions for her unnamed illness, present a compelling case that the seclusion was a consequence of the stigma Dickinson would have felt over her epilepsy; the shame of it and the fear of public humiliation propelled her from social gatherings up to the safety of her room. In 19th-century America’s polite society, epilepsy was associated with syphilis, insanity and masturbation.

Facebook Twitter Pinterest A different picture has been presented by the large number of famous people known to have been epileptic, including Neil Young.

Photograph: Rich Fury/Invision/AP

Dickinson lived a domestic life but also an alternative, epileptic one. The duality she expresses in her writing is often shared by others who have the condition. Again and again she teases at that which cannot be written; she can only go so far in revealing how the reclusive suffering might ultimately lead to an exalted existence. In her visionary poetry, Dickinson comes close to showing but not telling of that other life located in epilepsy: “And yet – Existence – some way back – / Stopped –struck – my ticking – through.”

Her poems find echoes in the work of the contemporary writer Lauren Slater, whose book, Lying: A Metaphorical Memoir (2000), is an account of her epilepsy. But then again it isn’t. For Slater is playing a sly game, having her cake and eating it, by suggesting early on in this meta-non-fiction book that the truth, as well as the narrator, is unreliable. Lying may all be made up.

Slater performs an impressive sleight of hand: she hides her epilepsy by revealing it, frankly – sort of. Any Jamaican, even if unfamiliar with postmodernist theory, would see straight away what she is doing. Jamaicans are schooled in the art of obfuscation. They call it “playing fool to catch wise”. Does Slater have epilepsy? What better revenge over your illness than to describe it and yet leave people wondering whether you were telling the truth. I would later recognise this quality in my brother Christopher, in his slippery and at times exasperating approach to his condition.

The first time that, as a teenager, Christopher failed to emerge from the bathroom and we had to break down the door to free him, we dismissed the fainting incident as bizarre but amusing. By the third occasion, following a battery of tests including a fitful night at a sleep deprivation clinic, I began to harbour the alarming suspicion that the fainting episodes were really epileptic seizures. I was a medical student at the time, and as reticent as my brother about entertaining such an unwanted diagnosis.

Facebook Twitter Pinterest Emily Dickinson lived a domestic life but also an alternative, epileptic one.

Photograph: A/AP

For as long as I could remember I’d been charged with watching over him. Christopher occupied a unique position in our family. He was the youngest, the most exuberant and happy. He seemed a blessed being who gladdened the heart of even the most miserable. It was as if, miraculously, his card had not been marked. At home in Luton, our tyrannical father Bageye always threatened to explode, but in the presence of Christopher he was disarmed.

After separating from Bageye, our mother had brought up seven children on her own. She’d been constantly on the move: rushing to the town hall to pay the rent; taking on overtime at Vauxhall Motors; popping over to the neighbours to borrow just enough to ward off the bailiffs. And in the meantime, could I keep an eye on my baby brother? It wasn’t too much to ask, surely. But it was a role I hadn’t been able to sustain as a student at the Royal London Hospital; and Christopher’s recent fainting episodes had taken her back to her decades-old daily anxiety.

For much of history only one form of seizure, the graphic grand mal, was ever recognised. But in the last century, scientists have been able to finesse the broad brushstrokes of our ancestors’ descriptions of epilepsy to discern numerous forms. Epilepsy, then, is an umbrella term under which many seizures fall. Still, there are two main categories: generalised seizures, in both hemispheres of the brain, for which there is no known cause (though inheritance is considered a factor in many cases); and focal or partial seizures, which arise in a particular damaged or sensitised part of the brain as a result of congenital disease or trauma, such as a blow to the head.

The story of epilepsy is a remarkable one. If it is a shameful, brutal and bruising tale it’s also one of redemption. People with the condition have resisted and survived purges and pathological attempts to eradicate them as if they were defective carriers of a contagious disease. Throughout history their castration has been proposed to rid humanity of their affliction. In the 1930s and 40s under the Nazi eugenics programme, the forced sterilisation of epileptics reached its apogee. But a different picture has also been presented by the large number of famous people known or suspected to have been epileptic. They include Julius Caesar, Joan of Arc, Fyodor Dostoevsky, Vincent Van Gogh, Harriet Tubman, Vladimir Ilyich Lenin and Neil Young.

None of this reassured Christopher. He refused to wear the recommended metal bangle engraved with the word “Epilepsy”, which he dismissed as reductive, branding him an epileptic. If he had a seizure in the street and was brought to a hospital’s emergency unit, he would never own up to the condition. The first time it happened, I was eventually summoned by the hospital. I arrived spitting feathers, angry and frustrated with him over what appeared to be a cavalier approach to his health and well-being. But on the walk back from the hospital Christopher described his seizure or the accident as a “fall from grace” – and a very public shaming from which, in his own way, through playing fool to catch wise, he sought and found protection.

On the few occasions that Christopher would consent to a frank conversation about his condition, I would invoke the names of these great figures who, in spite of their epilepsy, had led rich and rewarding lives. The response was always the same. “Van Gogh and Caesar!” Christopher would laugh sarcastically. “And how did it work out for them?”

Julius Caesar suffered at least four recorded episodes of epileptic seizures. They all came in the last two years of his life when he was in his 50s. The late onset was atypical. Epilepsy was more commonly believed to be a disease of childhood and puberty because it appeared to cease after marriage.

For centuries, physicians have wrangled over the likely cause of Caesar’s epilepsy. Sex was proposed as a cure yet it was also believed to be associated with epilepsy as an after-effect of syphilis. One of the more colourful theories about Caesar’s epilepsy was that it was a price of his womanising. But the most compelling aetiology centres on his hereditary predisposition, based on an above-average incidence of the condition in the Julio‑Claudian families. Historians have speculated that the sudden unexpected deaths of his father and great-grandfather were caused by epilepsy. Caesar’s descendants Caligula and Claudius were also said to have had it.

As for Van Gogh, there are numerous explanations for his bizarre behaviour, which culminated in him cutting off part of his ear before his eventual suicide in 1890. Yet his epilepsy appears to be spelt out in his correspondence with his brother Theo, and the neurologist Fabienne Picard is among those who think that the publication of the letters “makes the diagnosis of epilepsy indisputable”. The transcript of the doctor’s notes on Van Gogh’s admission to the St Remy psychiatric hospital on 9 May 1889 records that the artist had “suffered an attack of acute mania with visual and auditory hallucinations that led him to mutilate himself by cutting off his ear. Based on all the above, I consider that Mr Van Gogh is subject to attacks of epilepsy, separated by long intervals.”

Lengthy but lucid letters from Vincent to his brother came thick and fast in the late 1880s – a period in which he also produced hundreds of paintings and drawings. The letters chart how precarious and unpredictable life could be for someone enduring epilepsy, and its impact on their mental health. A few months later, on 5 October, Van Gogh appeared particularly anxious about the consequences of having any subsequent fit in public. He wrote to his brother that he was keen to become acquainted with the doctor in the next town to which he intended to travel, “so that in the event of a crisis, one doesn’t fall into the hands of the police and isn’t forcibly carried off into any asylum”.

Facebook Twitter Pinterest Van Gogh’s Self-portrait with Bandaged Ear (1889). Photograph: Peter Barritt/Getty Images/SuperStock RM

The eminent behavioural neurologist VS Ramachandran believes that Van Gogh’s epilepsy may have given him an advantage. In his reflections in “The Science of Art”, Ramachandran proposes a theory:

Van Gogh’s epileptic seizures in his temporal lobes may have actually strengthened neural connections between his visual object and face area and the amygdala, nucleus accumbens and other brain regions involved in gauging the emotional significance of what’s being viewed. Such a heightened attention and emotional response to visual images may have made him a more accomplished artist – his seizures enabling him to “attend” to certain critical dimensions more than you or I.

It is impossible to accurately trace the line between Van Gogh’s art and his mental condition. But it is indisputable that his final fecund years were a riot of fevered output both in his writing and his art. Hundreds of letters, more than a thousand drawings and almost as many paintings survive. His artist’s incontinence was a mark of his urgency to get down what he wanted to express. Epilepsy accelerated the process.

In his novel The Idiot, Dostoevsky’s protagonist Prince Myshkin’s debilitating epileptic seizures are occasionally compensated for by a moment of lucidity that precedes an attack. In his writing, Dostoevsky, who had been epileptic since childhood, began to perceive the possibility that his illness, indeed all illness, was a vehicle for transcendence: “As soon as he falls ill, as soon as the normal healthy state of the organism is disturbed, the possibility of another world begins to appear,” wrote the novelist, “and as the illness increases, so do the contacts with the other world.”

I would look forward to the magical moment when Chris was roused from his slumber after an attack Colin Grant

In the last decade, researchers in Australia have investigated the links between epilepsy and creativity. More than 60 artists with epilepsy volunteered in the University of Melbourne study “Sparks of Creativity” to investigate the hypothesis that “temporolimbic epilepsy … leads to altered functioning and hyperstimulation of areas of the brain that control the functions that most influence the creative process”.

The lead researcher is the artist Jim Chambliss, who was knocked unconscious in a car accident in 1986 and subsequently developed epilepsy. Chambliss’s thesis rests on the concept of “intrinsic perceptions” (spontaneously and independently derived from the brain in simple or complex hallucinations). Intrinsic perceptions occur, he believes, when sensory experience in people with focal epilepsy “is so altered by the neurological processes impacted by the misfiring of electrical impulses that what would be commonly perceived or understood as ‘real’ takes on surreal or dreamlikequalities”.

Facebook Twitter Pinterest Colin Grant (left) with his brother, Christopher

They ended up creating art, says Chambliss, “that is dreamlike, surreal or extraordinarily imaginative”. The study’s findings (which are themselves extraordinary) have not been reproduced elsewhere. Another recent paper on epilepsy and art concluded that if there was a common theme among its surveyed artists it was of the “unwanted psychological harm of some seizures provoking dark, frustrated imagery”.

There was always a moment as the phone rang in the early hours of the morning when my heart was flooded with dread. It could only mean one thing: Christopher had had another fit. The attacks were still random but their effect on him seemed incrementally deleterious; the cuts and gashes deeper and the bruises longer lasting.

On 4 August 2008, the phone rang at about 5am. But even after years of expectancy, of living on the threshold of amber alert, there was always a possibility of a false alarm. I took a deep diver’s breath and answered. It was my sister Sonia on the line. Christopher was at her flat, five minutes from where I lived. He was unwell. Could I come over?

When I got there, he lay dying on the kitchen floor. His giant frame filled the room. Either side of him two paramedics worked at massaging his heart back to life.

A third man in a green jump suit, who was already packing away some of the equipment, addressed me in a hushed conspiratorial voice. “Your brother’s been under 15 minutes now. There’s not much more we can do. After 15 minutes … It’s always upsetting for the team. But I think we’re going to have to stop. OK?”

“I’d like to try,” I said. “I know how.”

The paramedics moved out of the way and I knelt beside my brother and tried to depress his chest. There was no “give” in his torso. It seemed almost wooden. I was grateful that his eyes were already closed.

I had often pondered the connection between sleep and epilepsy. In his treatise On Sleep and Waking, reflecting on the relationship between the two, Aristotle drew the parallel: “Sleep is like epilepsy, and, in a sense, actually is a seizure of this sort. Accordingly, the beginning of this malady takes place with many during sleep, and their subsequent habitual seizures occur in sleep, not in waking hours.”

Observing Christopher in the throes of an epileptic seizure was disturbing and distressing. But in the mini drama of the fit, there was always one thing that I looked forward to: the magical moment when he was roused from his slumber after the attack. Watching over my brother in the aftermath I would implore him, as I did now, to wake up, to just awake. This time, he didn’t.