THE BROADER PICTURE : The art of schizophrenia

He was making his works of art before the word "surrealism" had even been coined, but Dali or Max Ernst would have had little to teach him. The reason is that August Natterer (1868-1933) was mad. The symptoms he described are recorded in his doctor's notes: "It seemed as if a broom was sweeping inside his chest and stomach. His skin had turned into fur; his bones and throat were petrified; in his stomach he had a tree trunk ... animals came out of his nose ... He explains the crackling of his knees as telephone calls by which the devil down below is notified of his whereabouts..."

Natterer, a carpenter by training, was also a painter who created arresting, cryptic images such as The Miraculous Shepherd (above). He was one of the many schizophrenic artists of the early 20th century whose disturbing works were collected by a German psychiatrist and art historian called Hans Prinzhorn, and published in his work Artistry of the Mentally Ill in 1922. Prinzhorn's collection - initially prompted by medical curiosity but informed by a broader aesthetic sense - has had a rough journey through the 20th century. Some of the works were used by the Nazis as examples of the "degenerate" modernist art they proscribed, and several of the artists (including Paul Goesch, who painted the Portrait, right) were killed, victims of the Nazis' plan to exterminate the mentally ill. The collection itself was all but forgotten for years.

However, with the emancipation of so-called "Outsider Art" in recent years, Prinzhorn has come in from the cold, and a major exhibition of the work he collected goes on show at the Hayward Gallery on 5 December. It ranges from immensely detailed religious scenes to a wood-carving of a double-headed hippopotamus, and an ink drawing of a smiling cat trapped inside a saxophone, entirely surrounded by written comments which flow in all directions. This last was by Johann Knopf (1866-1910), who also painted The Marvels of the Lead-Shot to the Sporting Gun (right).

For all their strange variety and differing levels of skill, certain key qualities unite these works. They are executed not for an audience but solely for the artist; and their apparent qualities of humour and frivolity are deceptive, because these pictures were made in a desperate and ultimately futile attempt to bring order to worlds that had collapsed in chaos. These qualities help to account for the fact that, whatever their charm and decorative achievement, these pictures are hard to look at. Inge Jadi, curator of the Prinzhorn collection, describes "the combination of fascination and secret terror that affect us on confronting these works. The radical Otherness that is formulated is our own, and yet inaccessible to our consciousness."

Prinzhorn collected the pictures at the prompting of the director of the institute where he worked in Heidelberg, but their effect on psychiatric understanding seems to have been limited. Rather, their impact was cultural. When the pioneers of Modernism set about smashing the conventions of 19th- century European art, the art of Africa and the Far East gave them powerful suggestions about where to go next. The works of the mentally ill, published for the first time in any quantity by Prinzhorn, fulfilled a similar function for the Surrealists. After that burst of success, however, they reverted to their customary place: what one scholar describes as "a curious limbo somewhere between the pathological exhibit and the work of art". !