I'm a clinical psychologist who worked at Topeka State Hospital (1962-76) and had a number of psychotics in both group and individual therapies. That was in an era when it was thought that people developed "insanity" due to some earlier unfortunate experiences which later became manifested by psychotic distortions of the ways they perceived and responded to reality. The plot for this movie was written during that era and reflected that belief -- (which is incorrect).
There are several different types of insanity: several forms of schizophrenia which is largely caused by genes and which typically becomes manifested in certain age ranges; manic-depressive psychoses, again caused by genes and typically manifested in certain age ranges; and a far more rare psychosis as a reaction to a strong psychic injury. The plot of this movie does not follow any of the developments now known to lead to a psychosis such as the lead character came down with. But it did make an interesting story for those unfamiliar with current practices or those who can temporarily suspend them.
Review of The Tenant
