Carl Jung Lexicon NYAAP

Loss of soul:

A concept borrowed from anthropology, referring psychologically to a state of general malaise.
The peculiar condition covered by this term is accounted for in the mind of the primitive by the supposition that a soul has gone off, just like a dog that runs away from his master overnight. It is then the task of the medicine man to fetch the fugitive back. . . . Some-thing similar can happen to civilized man, only he does not describe it as “loss of soul” but as an “abaissement du niveau mental.”[“Concerning Rebirth,” CW 9i, par. 213.]