Very interesting plot and characters. I identified as a psychologist, which I am and have worked extensively with DID. The switch was David taking on different alters that had been murdered.
This phenomenon might occur in the clinical setting, if the patient had contact with these other patients and their stories. Or especially was early on in treatment and having fear about the realization he has multiple altars and created these other alters as a defensive maneuver in treatment.
The movie included the act of a โsoul eaterโ, common during the Dark Ages when one needed spiritual healing.
A good movie for psychotherapists, psychologists and others treating DID.
Fascinating film, thanks!