Well, could be a case of multiple personalities or bipolar and I say this because I have 2 friends who are bipolar. You will not recognize the symptoms that easily. Rather these people absolutely appear normal to most people, unless you know the signs and this is the very challenge pharm company faces in clinical trials. They actually will impress you with their intelligence or their art work. My friends both are also highly educated and 'act' normal through medication, take away the medication the extreme in personality, the hallucination start. One friend told me that a person called Arobindo came to meet her one afternoon and they had a philosophical discussion. I was very impressed with her and asked her more about the person, on further enquires, I figure it was Swami Aurobindo, who of course was long dead. She was just hallucinating.
In fact, one of the reasons, pharmaceutical companies, can't find cure for many mental illness, it is because there isn't any parameter that can be truly applied to any models. FDA ,also do not know what could be the appropriate parameters to define such illnesses or if the benefit of a drug can out weights the risk because the drugs does have strong side effect and one often fail to know/quantify the long term effect of such drugs...