I’ve never been depressed. I’ve been down, sad, blue, but never depressed. But many family and friends, people I love, have been depressed. Some have tried to describe it to me. I learnt about depression as a medical student, but I’ve felt my understanding to be shallow. I wanted to know more about this pernicious disease, something that strikes at a person’s soul in a way that cancer, TB, or any physical disease do not.

I made some progress when I heard the biologist Lewis Wolpert talk about his depression. It came in fast and left him in unutterable distress. What I remember from his talk was the extreme severity of his depression. The pain was so unbearable that only suicide was the answer, but he didn’t kill himself. His account, and various writings (including a BMJ personal view by the brother of a man who killed himself) made me realise that to die by suicide is exactly comparable to dying from leukaemia: the disease has killed.

But finally I have come closer to understanding depression by reading William Styron’s Darkness Visible, an account of his depression. Styron, as most readers will know, was a leading American author, whose best known book is Sophie’s Choice. He died in 2006 aged 81.

His depression began in Paris in October 1985, and his attempt to describe it began with a lecture he gave at Johns Hopkins in 1989. This led to an essay published in Vanity Fair in the same year and the short book published in 1990.

From the beginning he recognises that he is trying to describe what is almost indescribable. “Depression is a disorder of mood, so mysteriously painful and elusive in the way it becomes known to the self—to the mediating intellect—as to verge close to being beyond description. It thus remains incomprehensible to those who have not experienced it in its extreme mode.” Certainly you can achieve only a shallow understanding from psychiatry textbooks, and doctors who have not experienced the extreme form must struggle to help those who suffer from it. There isn’t, I suggest, the same gulf between a doctor and a patient with cancer.

Styron quotes a clinician on our ignorance about depression: “If you compare our knowledge with Columbus’s discovery of America, America is yet unknown; we are still down on that little island in the Bahamas.” We don’t understand the disease, and despite tens of millions of antidepressant pills being prescribed every day, we don’t know how to treat it. “The most honest authorities face up square to the fact that depression is not readily treatable.”

The job of description is made still harder because depression has many manifestations. “It should be kept in mind,” writes Styron, “how idiosyncratic the faces of depression can be.” “But,” he insists, “never let it be doubted that depression, in its extreme form, is madness.” He likes the old, unacceptable word madness because it acknowledges both the extreme turmoil and our ignorance. Depression is too tame a word.

The whole book is an attempt to describe depression, and I recommend everybody who wants to try and understand more—and what clinician could not—to read it. But I have picked out some quotes.

“It is a positive and active anguish, a sort of psychical neuralgia wholly unknown to normal life.” Styron is here quoting William James, “The brain, in thrall to its outlaw hormones, has become less an organ of thought than an instrument registering, minute by minute, varying degrees of its own suffering.”

“[Depression] comes to resemble the diabolical discomfort of being imprisoned in a fiercely overheated room.”

“One does not abandon, even briefly, one’s bed of nails, but is attached to it wherever one goes.”

Styron emphasises again and again the protean nature of the disease, but one of the commonest features is a complete failure of self-esteem, an overwhelming sense of worthlessness. “Of the many dreadful manifestations of the disease, both physical and psychological, a sense of self-hatred—or, put less categorically, a failure of self-esteem—is one of the most universally experienced symptoms, and I had suffered more and more from a general sense of worthlessness as the malady had progressed.”

One thing I do remember from my limited training in psychiatry was always to ask if people with depression if they had considered suicide. Styron describes its powerful attraction: “Death was now a daily presence, blowing over me in cold gusts….Yet in truth such hideous fantasies [of suicide], which cause well people to shudder, are to the deeply depressed mind what lascivious dreams are to a person of robust sexuality.”

It was another book, All My Puny Sorrows, which taught me how some depressed patients will pursue suicide remorselessly. In her novel, Miriam Toews uses the experience of both her father and her sister killing themselves, to describe how the narrator’s immensely talented sister keeps trying to kill herself and eventually succeeds, using great cunning. The book is funny, and I thought it a remarkable achievement to write a story that spells out the agony of her sister and of herself and yet makes you laugh.

Styron, like many with depression, found no comfort from drugs: “But until that day when a swiftly acting agent is developed, one’s faith in a pharmacological cure for major depression must remain provisional.” I’m aware of the intense debate over the efficacy of antidepressants, and later this month I’m chairing a debate where the Danish epidemiologist Peter Gøtzsche will argue that psychiatric drugs do far more harm than good. Some of my friends and family have found that the drugs have helped, although some have got no help. The help may be a placebo effect, but I’ve come to the tentative conclusion that the drugs crudely dull the pain and that the name “antidepressant” with the implication that the drugs attack depression as antibiotics attack infection is misleading.

As you’d expect from a great writer, Styron inquires deeply into the causes of depression—and his general conclusion is that “The very number of hypotheses is testimony to the malady’s all but impenetrable mystery.” But he does think that loss is a cause, including in his own case: “Loss in all its manifestations is the touchstone of depression—in the progress of the disease and, most likely, in its origin. At a later date I would gradually be persuaded that devastating loss in childhood figured as a probable genesis of my own disorder….One dreads the loss of all things, all people close and dear.”

Styron’s depression persisted for months. One of the worst features of the illness is that you cannot imagine ever being well again. Eventually he was admitted to hospital. The drugs hadn’t helped, and the hospital was a ghastly place—but he was helped. “For in fact the hospital was my salvation, and it is something of a paradox that in this austere place with its locked and wired doors and desolate green hallways—ambulances screeching night and day ten floors below—I found the repose, the assuagement of the tempest in my brain, that I was unable to find in my quiet farmhouse…In the orderly and benign detention…one’s only duty is to try to get well.

Eventually Styron was ready to heal, and music was crucial to his recovery: “From unseen musicians came a contralto voice, a sudden soaring passage from the Brahms Alto Rhapsody. This sound, which like all music—indeed, like all pleasure—I had been numbly unresponsive to for months, pierced my heart like a dagger, and in a flood of swift recollection I thought of all the joys the house had known.” I can’t listen to that beautiful piece of music without thinking of Styron in that moment.

Styron ends by arguing, perhaps wrongly, that the storm will eventually pass. “Mysterious in its coming, mysterious in its going, the affliction runs its course. And one finds peace.” He concludes: “For me the real healers were seclusion and time.”

Richard Smith was the editor of The BMJ until 2004.