I do hope you're being obtuse. Maybe you simply don't realize that you're doing the equivalent of telling a rape victim that at least he or she "got some" or pushing a person in a wheelchair over and laughing because they can't get up or writing a story about Nazis beating Jews and claiming that it's slapstick. It's a dangerous and treacherous footing, glorifying another person's problems for amusement.

While I'm not going to stop you I can understand where other people might get upset. I have a great aunt in the asylum and my parents never let me meet her. I even came close to developing such a disorder myself. When I was young and being bullied I blacked out and "someone" took over and chased away the bullies. My mother claimed it was an angel. Luckily, being the intelligent sort I refuted this, figuring a real angel would have conspired to prevent the event taking place at all rather than resort to violence. As it was, I recognized the possibility of going insane and was terrified. If I hadn't, if I had taken my mother at her word and didn't doubt the angel aspect, I might very well have created the alternate persona that enjoyed beating up people and probably, eventually killing people all in the name of God.

I can't begin to tell you how terrifying it is to awaken somewhere else, having no memory of what you've done in the past or what it's like being told by others what you had done. A mental illness is created when the brain tries to protect itself and something goes wrong. It's where the brain sacrifices its future health in order to survive the present. 

The truly deplorable part is that you want to portray someone that is sick... but in a world where that sickness is cultivated, cherished and protected by those that should be trying to heal such a person. That's fairly depraved. That's why I was suggesting some other means of possessing an alternate persona rather than being insane.