Adverse reactions to stopping some classes of antidepressants cold turkey have been documented, and many of the mass murder shooters were (at one time) on such drugs, or off their meds.
I had already clicked the link and read it. I’m not saying he is a sociopath. But he well might be. If so, he cannot feel empathy and doesn’t feel remorse. Drugs can’t make him a sociopath or unmake him one. It’s something that happens to a person very young, and for which there is no known cure.
All I’m saying is that if he is a sociopath, his ‘Dr. Jekyll’ half will never feel any genuine remorse or empathy. He might fake it for effect, but even a halfway decent psychiatrist could unmask the pretension. Unfortunately we live in an age where sociopathy is more common than in the past. Many societal factors coalesce to create an environment conducive to such personality disorders. It’s generally the most defenseless people in the sociopath’s environment that pay the highest price.