It is actually quite accurate as to the life of someone with BPD. If you don't know, it is about a scientist who drinks a potion to become an evil alter ego of himself, and then he goes out and commits horrible acts. It's like a drug, and when it wears off he turns back to himself. The goal of this drug was to make it so that he could exercise his evil side freely, ridding his good side of the unconscious primal urges and allowing him to go even farther for science.

At some point he begins to transform randomly into this alternate form. He is constantly in fear of the change. Towards the end of the book he kills himself to escape it. I thought it was a surprisingly accurate portrayal of Borderline Personality Disorder. 