Wendigo is a mythological creature or evil spirit originating from Algonquian folklore. The concept of the wendigo has been widely used in literature and other works of art, such as social commentary and horror fiction. The wendigo is often said to be a malevolent spirit, sometimes depicted as a creature with human-like characteristics, which possesses human beings. https://en.wikipedia.org/wiki/Wendigo
Seems skeptical, at best, if the psychosis is even real and not just a retroactive diagnosis based on third hand story telling. https://en.m.wikipedia.org/wiki/Wendigo
No, the indigenous people who created the "mythical creature" say that they mean it literally to describe a real thing and that thing is the psychosis. The modern diagnosis comes from their description of the psychosis.