Actualy, I have come across this word and idea before-- it has been used to define self canabalism-- from the gross-- picking ones nose, and eating it! to people who gnaw and bite their cuticles,(and swallow the bits of flesh,) or bite the insides of their mouths, or in other ways self consume.

Autophagy is not a sign of good mental health-- but some examples are more extreme and unhealth than others.