I have believed I was many things; Christ returned, an Alien, The President, an alter personality. The steadfast delusion though, that is present even among my other beliefs, is that I am a subject in a brain study and that the ‘other me’ is one of the researchers. I have an entire other life that I am keeping from myself with the help of the world. My whole world is staged and fake. Scientists who are controlling my brain (cuz I said they could) won’t allow me to access memories of the real world or my other life.
So…I believe I am someone else and I don’t know who, except I think I am a scientist who gave permission to do this to me. I don’t know what I am like, what I think about things, if I am straight or gay, if I am conservative or liberal, if I believe in God or don’t. I only know ‘this’ life has been stage-set, controlled and monitored for many years. I do believe I am someone else but that someone is me and I don’t know anything about me.
Yes. When I was 23 years old and in nursing school, I believed that I was Florence Nightingale reincarnated.
I’ve had the delusion that I’m either God or Jesus a few times. I’ve also had delusions that made me believe that I was the Antichrist and that the only way I could stop the apocalypse from happening is to kill myself. Psychosis is one hell of a thing. 
The voice in my head always talks about wanting to mix his personality with mine and saying the personalities belong together. He is a bad guy so it weirds me out. I feel like I get a little of his personality. Never enough to become a bad guy but enough to want to climb out of my body. Feels crowded in here.
His biggest control over me is shutting down my motor skills and attention span. If he doesn’t want me to do something I won’t do it no matter how badly I want to…
I believed once that I was me. That belief got shattered when I got schizophrenia.
This is really sappy , but your comment made me cry I relate to it so much , thank you
I thought that I was a demon. I can relate
I had a psychotic break (bad one) where I believed I was supposed to die and merge with God so I cut my wrist and took all my meds. I felt like I was out of control of my behavior. I still struggle with ideas that I am connected to God etc but I am not psychotic. Just delusional.
yes, psychosis is a hell of a thing.