“The Scream,” an 1893 painting by Norwegian artist Edvard Munch, was vandalized by its creator, curators at a Norwegian art museum found.

The painting of a person whose face is contorted against a surreal landscape is one of the most famous in the world. Controversial in its own day, the National Museum of Norway notes an inscription on the painting that reads “Can only have been painted by a madman” was first noticed 11 years after Munch completed the piece.

The inscription was thought to be the work of a frustrated viewer, though new research reveals its true origins. A team at the museum discovered those words were inscribed by the artist himself. History suggests Munch was offended by questions of his mental well-being from medical student Johan Scharffenberg who attended a showing of the expressionist painter’s work.

"The theory is that Munch wrote this after hearing Scharffenberg's judgment on his mental health, sometime in or after 1895,” Mai Britt Guleng, a curator at the National Museum, said in a statement.

Researchers look closer at inscription on Evard Munch's iconic painting, "The Scream Researchers look closer at inscription on Evard Munch's iconic painting, "The Scream" Photo: The National Museum of Norway

Known variably by a German title that translates as "The Scream of Nature" or in Norwegian as "Shriek," according to the narrative, “The Scream” was viewed with skepticism from the art elite. Henrik Grosch, who was the director of the Norwegian art museum in the late 1890s, is known to have said the painting confirmed that Munch was not a serious man “with a normal brain.”

Munch made several iterations of his works, though the Norwegian museum has the original version of “The Scream.” The back is a partial effort that Munch completed on the other side.  The words were written on the painting after it was completed.

Using infrared photography, museum workers were able to view the writing in further detail without causing damage to the painting itself.

“You have to get quite close to see the inscription. We seldom find such inscriptions on paintings, particularly not on one of the world's most famous ones,” the curator said Monday. “Given that it's such an important work in the history of international art, the inscription has received remarkably little attention.”

Can only have been painted by a madman" penciled on top of Evard Munch painting, "The Scream "Can only have been painted by a madman" penciled on top of Evard Munch painting, "The Scream" Photo: The National Museum of Norway

CNN reported that art historians believe Munch drew inspiration for the painting after going through a bout of emotional distress. Rarely on show since it was stolen in 2004, the piece has gone through extensive restoration ahead of the opening of a new Norwegian art museum next year.

Researchers say the painting has deteriorated significantly, mostly as a result of human breath.

A pastel version of the work sold at auction for nearly $200 million to an anonymous buyer in 2012, a record price at the time.

Evard Munch vandalized "The Scream" with his own hand Evard Munch vandalized "The Scream" with his own hand Photo: The National Museum of Norway