By Joyce Carol Oates

If illness is a foreign country, mental illness is a yet more foreign country, one with a special stigma. No one takes pride in visiting this country with its imprecise, ever shifting borders and murky language; its frequent mimicry, as in nightmare parody, of "normal" behavior; its myriad terrifying symptoms that seem, to the healthy, simply "all in the head." Our common-sense culture can generously accommodate physically ill individuals, but the mentally ill can be suspected of exaggerating, even of imagining, their own problems. Their minds, or brains, must have "caused" their ailments, since we have only the testimony of the afflicted to bear witness to what is "ill" in their lives.

Depression, more poetically known as "melancholia" until the 17th century, has surely always been with our species, like the so-called common cold and that elusive malady, the flu. Its history has been as much theological and psychological as medical; though contemporary thinking has almost totally medicalized depression, and its treatment today is far more likely to be pharmacological than any religious or psychoanalytic ritual involving "talk," there is still a nature/nurture debate about its origins: is depression genetically inherited, or is it provoked by one's environment, childhood, gender, politics, misfortune?

As Andrew Solomon suggests in this exhaustively researched, provocative and often deeply moving survey of depression, depression is "usually the consequence of a genetic vulnerability activated by external stress." For Solomon, for whom depression has been far more than an academic subject, the most useful vocabulary is often metaphorical: depression is a tree choked and smothered by a parasitic vine, yielding only "a few desperate little budding sticks of oak"; depression is "like feeling your clothing slowly turning into wood on your body"; it's "like trying to watch TV through terrible static"; "like going blind"; "like going deaf." In Emily Dickinson's yet more eloquent words, depression is "a funeral in the brain." Yet paradoxically, and here is where the foreignness of mental illness is most pointed, those afflicted with depression are often ambivalent about it, as no one is ambivalent about physical illness: "It was also in depression that I learned my own acreage, the full extent of my soul," Solomon declares. And, even more rhapsodically, in the concluding pages of the book's final chapter, "Hope":

"Curiously enough, I love my depression. I do not love experiencing my depression, but I love the depression itself. I love who I am in the wake of it. . . . I have discovered what I would have to call a soul, a part of myself I could never have imagined until one day, seven years ago, when hell came to pay me a surprise visit. It's a precious discovery."

"The Noonday Demon" is an inspired title for a survey of depression, deriving from biblical texts that include the King James version of Psalms 91:6 ("the destruction that wasteth at noonday") and the Roman Catholic Douay version, which refers to "the noonday devil." Though one might wince at the theological metaphor, with its suggestion of demonic possession -- a primitive stage in our comprehension of mental illness we like to believe we've advanced beyond -- still the poetic figure of speech is a powerful one that no amount of scientific terminology and matter-of-fact discussions of serotonin deficiency, neurotransmitter systems or tricyclics can match. Though we "know" better, we tend to "feel" symbolically. Depressive personalities, and their close kin suffering from bipolar disorder (formerly known as manic-depression), are prone to romanticizing their neurochemical-based illnesses, for these illnesses intensify isolation, inwardness, self-analysis and self-dramatization. "In the throes of depression," Solomon says, "one reaches a strange point at which it is impossible to see the line between one's own theatricality and its reality of madness."

"The Noonday Demon" originated in 1998 as an article on depression in The New Yorker that stimulated an extraordinary response among readers. It's both an intensely personal document, a memoir of the author's several breakdowns in the wake of his mother's harrowing experience with ovarian cancer, and a more conventional, ambitiously encyclopedic study of depression and suicide. In its mixture of the personal and the impersonal, the confessional and the analytical, "The Noonday Demon" will remind readers of Kay Redfield Jamison's "Unquiet Mind" (1996) and "Night Falls Fast" (1999), the latter of which Solomon quotes throughout his text. In its informed discussion of psychotropic drugs, including the ever-popular Prozac, it will remind readers of Peter D. Kramer's "Listening to Prozac" (1993). Though oddly missing from Solomon's 34-page bibliography, William Styron's spare, elegiac memoir of breakdown and depression, "Darkness Visible" (1990), would seem to have been a model as well.

Yet there is much in "The Noonday Demon" that is original and vividly recounted. Solomon's account of his mother's courage and integrity in the face of her deteriorating physical condition and her decision to commit suicide by way of an overdose of Seconal, taken in the presence of her family, is particularly moving, and might have been developed into a book-length memoir. This sensitive material is rather swamped by the many reportorial pages that surround it.

Readers should not be discouraged by the opening chapter of "The Noonday Demon," titled "Depression," which is the least coherent chapter in the book, lurching from point to point as if awaiting a principle of inspired organization that never arrives. The second chapter, "Breakdowns," is the true dramatic beginning: "It was when life was finally in order and all the excuses for despair had been used up that depression came slinking in on its little cat feet." From this point onward, Solomon is more certain of his somewhat unwieldy material. Even when writing more or less straightforward journalism, Solomon writes engagingly; his style is intimate and anecdotal, and often bemused. Looking back on his depression, he notes his skewed logic: "I have often wanted to kill myself for a month." He assures us that his love of sky diving, a "para-suicidal activity" for others, isn't suicidal in his case (though he discusses it in the chapter titled "Suicide"). He's frank in his enthusiastic endorsement of psychotropic drugs: "It is hard for me to write without bias about the pharmaceutical companies because my father has worked in the pharmaceutical field for most of my adult life." (There are times when "The Noonday Demon" reads like a pharmacologist's handbook, thrumming with the Brave New World music of mellifluous brand names: Celexa, Xanax, Viagra, Zyprexa, Effexor, Wellbutrin, BuSpar, Depakote, Klonopin, Halcion, Restoril, Zoloft, Paxil et al.) But Solomon also speaks optimistically of electroconvulsive (shock) treatments and of psychoanalytic and "talk" therapy, all of which he has tried.

Perhaps more controversially, Solomon discloses his deliberate and repeated attempts to infect himself, through unsafe sex, with the AIDS virus in 1995, in the grip of depression: "It was not my intention to die slowly of AIDS; it was my intention to kill myself with H.I.V. as my excuse." Solomon notes his several violent episodes triggered by depression (or by the potent drug cocktail that was prescribed for him) when he "began plotting murders in my mind," and assaulted a lover whom he suspected of betrayal. "I attacked him," he writes, "with a ferocity unlike any I had experienced before, threw him against a wall, and socked him repeatedly, breaking both his jaw and his nose. He was later hospitalized for loss of blood. I will never forget the feeling of his face crumpling under my blows. . . . It took a powerful summoning of my superego to save me from strangling him."

Seemingly unaware that such an assault is a felony, Solomon reflects: "Engaging in violent acts is not a good way to treat depression. It is, however, effective. To deny the inbred curative power of violence would be a terrible mistake. I came home that night covered with blood -- mine and his -- and with a feeling of both horror and exhilaration. I felt tremendous release." Unfortunately, violent acts are not so "curative" or cathartic for their victims.

In addition to Solomon's memoirist material, the most rewarding chapters in "The Noonday Demon" are "Populations" (a persuasive synthesizing of sociological theories on depression, focusing on gender and feminist issues), "Politics" (an investigative report into mental health hospitals) and "History" (a succinct history of depression from ancient Greece to the contemporary United States, theories and treatments). Solomon's thumbnail critique of Michel Foucault's "Madness and Civilization" is witty and persuasive: "Foucault makes good reading, but the influence he has had is much crazier than the people who are his subject. Depressed people cannot lead a revolution because depressed people can barely manage to get out of bed and put on their shoes and socks."

Amid so much information, the author might have been more discriminating and skeptical. Some of the statistics he quotes seem plausible to the layman: approximately 19 million Americans suffer from "chronic depression." Others seem unprovable: "Depression claims more years than war, cancer and AIDS put together. Other illnesses, from alcoholism to heart disease, mask depression when it causes them; if one takes that into consideration, depression may be the biggest killer on earth." Nearly 400 pages later, Solomon wonders, "If depression is an illness that affects as much as 25 percent of the people in the world, can it in fact be an illness?" And what is one to make of the bizarre claim that "in the long run," depression "makes good people better" and "bad people worse"? A sleep expert opines that depression might have been beneficial in the development of Homo sapiens since the afflicted "probably lived long and had lots of babies." (This will be news to the suicidal, anorexic and amenorrheic females, and impotent males.) Solomon has not resisted the animal anecdote: a circus octopus trained to do tricks for rewards of food fell into a depression when the circus disbanded, gradually lost his color and stabbed himself to death with his beak. One for "Ripley's Believe It or Not."

Eventually so all-inclusive is the concept of "depression" in "The Noonday Demon" -- and our need to be treated for it with expensive drugs -- that by the book's conclusion I was drawn to reread much of Charles Mackay's classic "Extraordinary Popular Delusions and the Madness of Crowds" (1841), a study of epidemics of delusion through our seriocomic human history, and Elaine Showalter's "Hystories: Hysterical Epidemics and Modern Culture" (1997), in which Showalter suggests that hysterical epidemics require at least three ingredients: physician-enthusiasts and theorists; unhappy, vulnerable and suggestible patients; and supportive cultural environments promulgated through the mass media. "A unified field theory of a vague syndrome" provides an explanation for its various confusing symptoms, Showalter says, and, not incidentally, one might add, makes for brisk business in some quarters, notably the pharmaceutical.

Over all, however, "The Noonday Demon" is a considerable accomplishment. It is likely to provoke discussion and controversy, and its generous assortment of voices, from the pathological to the philosophical, makes for rich, variegated reading. Solomon leaves us with the enigmatic statement that "depression seems to be a peculiar assortment of conditions for which there are no evident boundaries" -- exactly like life.

Joyce Carol Oates is the author, most recently, of the story collection "Faithless: Tales of Transgression" and, under the pseudonym Rosamond Smith, the suspense novel "The Barrens."