On July 5, 1945, the French painter Jean Dubuffet set off for Switzerland accompanied by two fellow Frenchmen, the publisher Jean Paulhan and the architect Charles-Édouard Jeanneret, better known as Le Corbusier. The Swiss tourism board had organized the trip with the hopes that the men would return to Paris with a new view of Switzerland. Paul Baudry, the cultural ambassador of French-Swiss tourism, had organized for them to eat at the top restaurants, take in the rolling hills and meadows, and go to the Matterhorn.

But Dubuffet had little interest in all that. “He ran around the asylums,” Paulhan later wrote, collecting “different drawings and gouaches.” In Paris, Dubuffet had already begun purchasing art made by people who had been deemed mentally ill, but it was in Switzerland, across roughly half a dozen institutions, where he gathered the bulk of what would become his collection.

He broke away from the group and went first to the Waldau Asylum, outside Bern, where he spoke with Walter Morgenthaler, a Swiss psychiatrist who had worked at Waldau as a medical assistant, collecting thousands of works made by the asylum’s patients. Dubuffet saw first the art of Adolf Wölfli, a sexually abused orphan who had been interned at Waldau after becoming an abuser himself. Wölfli’s twenty-five-thousand-page masterpiece combines texts, drawings, collages, and musical compositions that together outlined a reimagined history of his childhood and a fantastical, mythological future he dreamed up for himself. Dubuffet recognized the work’s brilliance immediately. Upon seeing it back in Paris, his friend, the surrealist painter André Breton, called the work “one of the three or four most important oeuvres of the twentieth century.”

In an asylum in Münsingen, a municipality inside the canton of Bern, Dubuffet also collected the work of Heinrich Anton Müller, an illustrator with severe depression. Müller’s work evokes the childish drawings of Paul Klee and Marc Chagall but also taps into Swiss folk, medieval, and modern art. With no knowledge of art history, Müller was unshackled from a rigid style. In Hermine, he drew what appears to be a biblical Eve—but in green and orange pencil. He has her holding grapes, beneath a tree, with a serpent gliding up toward her pregnant belly. Like most of his figures, she has great big eyes and a melancholy look. Thanks also to his frequent use of white chalk, Müller’s figures look like ghosts, creatures that understand—and accept—the brutalities of life.

Dubuffet continued throughout Switzerland, meeting with and collecting the art of the schizophrenic painter Aloïse Corbaz at La Rosière, an institution near Lausanne, as well as the sculptures of Joseph Giavarini, who had been imprisoned in Basel for the impassioned murder of a woman who had spurned him.

Dubuffet took all of these works back to Paris but found the art to be unpopular in French salons. Only a select few took interest—fellow outsider artists or surrealists like Breton—so two years later, in 1947, Dubuffet wrote The Art Brut Manifesto, laying out the cultural necessity and aesthetic beauty he believed was ignored by the mainstream art world. A year after that, he, Breton, and the critic Michel Tapié founded the Compagnie de l’Art Brut, which collected works from outsiders and the mentally ill.

In the end, Dubuffet’s movement never caught on with mainstream artists, galleries, and auction houses. The works that he had collected between France and Switzerland went on show only twice, in 1949 at the Galerie René Drouin and later, in 1967, at the Musée des Arts Décoratifs, both in Paris. And yet its influences have been far-reaching, inspiring the filmmaker Jean Cocteau, the painter Joan Miró, and the anthropologist Claude Lévi-Strauss, among many others.

Art brut, or raw art, is “raw because it is ‘uncooked’ by culture,” John Maizels writes in Raw Creation, “raw because it came directly from the psyche, and, in its purest form, touched a raw nerve.”

In his own words, Dubuffet called art brut “works created from solitude and from pure and authentic creative impulses—where the worries of competition, acclaim, and social promotion do not interfere—are, because of these very facts, more precious than the productions of professionals.”

The culture of mainstream art, Dubuffet reasoned, was driven by an urge to assimilate every inventive artistic development, and thereby robbed it of its power. Mainstream art would be sure to, Maizels writes, “asphyxiate genuine expression.”

In 2013, the French government took what was once Victor Hugo’s house on the Place des Vosges and nationalized it, turning it into the Maison de Victor Hugo. Best known as a place where fans and tourists come to see the bed in which he died, it is a museum in which large exhibitions are seldom put on. But this winter, the museum is showing four European collections of art created by mentally ill patients, including those from which Dubuffet collected. The exhibit, called “La Folie en Tête,” or, roughly translated, “Madness on the Mind,” includes no well-known artists. (Most of them, in fact, are without last names or are entirely anonymous.) It is one of the most striking shows to be put on in the French capital in years. Across the entirety of the house’s second floor, the show underscores the way in which art brut directly informs mainstream art culture.

What is now considered edgy contemporary art—surrealism but also minimalism, found objects, even much of abstract expressionism—has its origins in the works of outsiders. In Morgenthaler’s collection, the works at once refuse to operate within the confines of art history‚the art he collected is especially childish, earnest, and done in “innocence” of outside knowledge—while also predating the art of future famous mainstream artists. For instance, throughout the twenties, Marie Füri, an essentially unknown artist and mentally ill woman who suffered from epileptic seizures, made dozens of drawings at Waldau, including an untitled lead-pencil work on paper comprised of tight, thin, continuous cursive ovals spanning the entire page. It is a work that might be easily confused for a study of Cy Twombly’s 1968 untitled drawing of white scribbles on a blackboard. While Twombly’s version sold at Sotheby’s just over two years ago for $70.5 million, Füri’s work is virtually unknown.

In the collection of Auguste Marie, the chief physician of the Sainte Anne Psychiatric Hospital in Paris from 1920 to 1929 and a consultant at the asylum in Villejuif for the two decades before that, the untitled drawing-cum-collage of a mentally ill man named Victor-François (his last name is unknown) uses Chinese ink and yellow-tinted pencil on transparent paper to create a complex figuration of a Christ who appears to have gone insane. Christ’s eyes are formed with squiggling circles, making it appear as though he has either gone mad or, more intriguingly, that a form of madness has become divine. Such religious parody would elude more mainstream sensibilities until, arguably, up until the late twentieth century, when artists like David LaChapelle and Maurizio Cattelan came to the fore. In the self-aware Objects of the Insane, an anonymously constructed wooden box full of tightly arranged black buttons, strings, rusty nails, and bits of metal precedes Marcel Duchamp’s found objects by well over a decade. In the work Contemporary History, a patient named Albert G. gorgeously deploys inky geometrical shapes and lines—pure automatism—in a style so original that it would only be taken up more than two decades later by André Masson. And in another work, an anonymous artist cut a German newspaper into a triangle and then colored in, seemingly at random, between many of the letters in orange, red, and green colored pencil. Of course, the work means absolutely nothing, and yet its just-off-kilter composition, its tiny vertical folds and brief bits of vertical print, are so stunningly new that when you see the date is 1897, you think there’s been a massive typo.

The question that these deeply original artworks pose is both simple and deceptive: What is art supposed to do? Is it meant to be in dialogue with history—to play within the confines of a certain style or set of visual rules—or is it meant to be an unfiltered portal to the subconscious, even if—especially if—that subconscious is perverse?

In the contemporary art market, outsider art remains undervalued. But if you look at what is most evocative and what, importantly, has the rare distinction of originality, art brut, raw and unfiltered, fulfills the distinction—the madness of the mind made manifest.

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It’s a common idea that at least a trace of madness undergirds the creative impulse. But the notion that insanity and art go together is also a potentially harmful myth, perpetuated in part by a desire to justify bad behavior and in part by the need to ascribe genius to a fundamentally different state of being.

Scientifically, the link between creativity and madness is well studied but not concrete. It is true that “distinguished artists,” according to a study from Johns Hopkins’s Kay Redfield Jamison, tend to have depressive illnesses at a rate of about ten to thirty times higher than the population at large. Poets, especially, tend to be the most “tortured” and psychologically “damaged,” according to a decade-long study from the University of Kentucky’s Arthur M. Ludwig. There’s no getting around the fact that artists have especially high rates of mood disorders, including bipolar disorders and depression. While these illnesses are not a prerequisite to creativity, they do tend to accompany the artistic mind.

One popular idea is that people who have mood episodes have brains that are more accustomed to extreme emotional swings, and thus their brains are more adaptive to synthesizing disparate thoughts, a process that is often considered the crux of creativity. Likewise, the manic period experienced by those with bipolar disorders is similar to the high felt during the creative process.

“The idea that mania has an intrinsic relationship to creativity is based in part on retrospection of what it feels like to be in a state of manic excitement, a state that feels like manic power, euphoria, endless energy and optimism,” says Sybil Barten, an emeritus professor of psychology. “On the face of it, these feelings might well be those that characterize the process of creation.”

But the myth of the tortured artist can also be harmful. Depression, alcoholism, shifting moods—these are not especially productive states. Creativity still requires discipline as well as long periods of energy and focus. Even the classic examples of the “successful mad artist” would probably have been better off without their mental disorders. Vincent van Gogh, for instance, might have been able to create a good deal more artworks had his mental illness not interfered. “There is evidence in his letters that he didn’t view these problems that were visited upon him as enhancing his creativity,” says Jane Kromm, a professor of art history, “but rather was very worried that his peaceful periods of accomplishment would be stolen from him.”

Indeed, many successful creative people make a point to impose stability and normalcy on their lives. In a longitudinal study, Nancy Andreasen, who is known as one of the founders of the psychological study of creativity, found that successful artists typically follow relatively rigid schedules in which they purposefully set out time to write each day. Gustave Flaubert’s quote—“Be regular and orderly in your life, so that you may be violent and original in your work”—comes to mind.

Successful artists, according to Andreasen, also stay close to friends and family, knowing this is vital to their happiness. They subscribe to the Freudian definition of health: to love well and to work well. And yet they also don’t fully distance themselves from the emotional swings they feel. Many of the people she studied had serious mood disorders, which hurt their ability to create when they were in the throes of them. But these experiences also provided helpful material that they could later use—what William Wordsworth called “emotion recollected in tranquility.”

So perhaps the most pressing question is not, Are madness and creativity linked?—the answer seems to be yes, although not in the romantic ways we tend to assume—but rather, What should one do if mental illness has struck? While mental illness may not lead directly to creativity, artistic projects tend to be some of the best outlets for dealing with mental disorders.

William A. F. Browne, who directed the Crichton Royal Hospital in Dumfries, Scotland, and whose collection is on show at the Maison de Victor Hugo, believed that providing his patients with artistic activities was the most “moral treatment.” Compared to the Victorian nightmare of straitjackets and electroshock therapy, a pencil and a piece of paper certainly seem like desirable instruments for rehabilitation.

In the works on display at the Maison de Victor Hugo, the humanity of the patients shines through, a humanity that had largely been denied them both in and out of the hospital. Museumgoers often expect art to convey a distinct, singular message. It is not an overstatement to say that to then not “get” that message is to feel as though you don’t have a soul. It’s an idea evocative of Kazuo Ishiguro’s Never Let Me Go, in which boarding-school students—who we later discover are clones—are asked to submit their drawings to the school’s administration. The goal is to determine whether or not they have a deeper personhood. “That’s the whole thing about art,” says Tommy D, one of the three clones followed throughout the novel. “It says what’s inside of you; it reveals your soul.”

But with this exhibit, that expectation is cast aside. One is free to experience the work as pure emotion, devoid of meaning or intention.

Much of the art shown in “Madness on the Mind” was created before and during the two world wars. In the midst of World War II, Carl Schneider, who had directed Hans Prinzhorn’s collection of art by mentally ill asylum patients for years, was assigned by the Nazis to become the head of the so-called T4 Program, which stipulated “the extermination of physically and mentally handicapped adults.”

Although Schneider had once worked closely with the mentally ill artists and their works, he now refused to look at it. It made those he was asked to kill too human. In looking, their work became them—and they became their work. In their art, their souls shone too brightly.

Cody Delistraty is a writer and critic in Paris.