Police said the man, who needs to take medication, could be violent towards himself or others.
He has short black hair, brown eyes and was last seen wearing jeans and a hooded sweater.
He disappeared from La Clef d’Arc, a government housing centre in Montreal North, after he went outside for a cigarette.
Police said he could still be in the area, possibly in a park or shopping mall. He’s described as being reclusive and disorganized.
People who may have seen Betournay or who have information about him should contact the Montreal police at 514-393-1133.