A TINY message hidden in Edvard Munch’s famous painting “The Scream” was written by the artist himself, a new investigation of the work has found, finally resolving one of modern art’s most enduring mysteries.

The message “Can only have been painted by a madman,” scrawled and barely visible in the top left-hand corner of the painting, has been the subject of debate for decades and was widely believed to have been an act of vandalism by a viewer of the piece.

But extensive research by the National Museum of Norway has revealed that Munch wrote the phrase himself.

The Expressionist masterpiece is one of the most celebrated works of modern times, heralded as a timeless depiction of human anxiety. The subject’s anguished face has become so familiar that it was recently given its own emoji.

Curators used infrared technology to analyze the message, which was added on top of the finished painting, comparing it with Munch’s notes and letters and studying events around the time of the work’s first public showing.

“The writing is without a doubt Munch’s own,” Mai Britt Guleng, the museum’s curator, concluded. “The handwriting itself, as well as events that happened in 1895, when Munch showed the painting in Norway for the first time, all point in the same direction.

A pastel version of the painting fetched nearly US$120 million at a Sotheby’s auction in New York in 2012.(SD-Agencies)