In modern pysichiatry the wendigo lends its name from a form of physchosis 
known as 'Wendigo Physchosis' which is characterised by symptoms such as; 
an intense craving for human flesh,
intense fear of becoming a cannibal.

Wendigo physchosis is described as a culture-bound syndrome. In some First Nation
communities other symptoms such as insatiable greed and destruction of the 
enviroment are also thought to be symptoms of Wendigo Physchosis.

In historical accounts of retroactively diagnosed Wendigo Physchosis, it has 
been reported that humans become possessed by the wendigo spirit, after being in 
a situation of needing food and having no other choice beside cannibalism. In
1661, The Jesuit Relations reported;

"What caused us greater concern was the news that met us upon entering the Lake,
namely, that the men deputed by our Conductor for the purpose of summoning the
Nations to the North Sea, and assigning them a rendevous, where they were to
await our coming, had met their death the previous Winter in a very strange 
manner. Those poor men (according to the report given us) were seized with an 
ailment unknown to us, but not very unusual among the people they were seeking.
They were afflicted with neither lunacy, hypochondria, nor frenzy; but have a 
combonation of all these species of disease, which affects their imaginations
and causes them more canine hunger.  This makes them so ravenous for human
flesh that they pounce upon women, children and even upon men, like veritable 
werewolves, and devour them voraciously, without being able to appease or glut 
their hunger- everseeking fresh prey, and the more greedily the more they eat.
This ailment attacked our deputies; and, as death is sole remedy among those 
simple people checking for such acts of murder, they were slain in order to
stay the course of madness"