Local police warned that if the man drinks any alcohol or takes drugs, there is a risk that he will be "very dangerous". The man has been previously convicted for aggravated violence and rape and was under psychiatric care.
He was last seen wearing a brown leather jacket and black jogging trousers, and has a deep wound on his right arm and a flag tattooed on his left shoulder. He has been described as 180 centimetres tall, heavy bodied, and with a rectangular face. He has dark blonde hair, green eyes, crooked teeth and a straight nose.
"If you see him, ring 112 immediately. Do not talk to him," Lars Ånestrand of the local police told the TT news agency.
Six police patrols are on the lookout for the man, who is believed to have taken a bicycle after escaping, but Ånestrand referred to the search as a "needle in a haystack" job.
The 54-year-old was convicted for aggravated rape in 1987, and was admitted to the Karsudden ward in 2005.
The man has been under psychiatric care for 26 years, during which time he has committed several crimes, including coercion, theft, and violence against officers.