I'm not sure that your phenomenon exists to any substantial extent in the real world. Also, keep in mind that categorizing mental illness is in general difficult. It isn't that uncommon to have issues where one psychologist will diagnose someone as schizophrenic, while another will say the same person is bipolar, etc even as everyone agrees there's something deeply wrong with them. So even if your people in your like-the-Joker category exists in some form, it may be that there isn't any term for them.