Can I be possessed as a Christian?

Can I be possessed as a Christian?

I have been told and from what I can tell I can’t but maybe I am missing something. I feel as though it is just one demon and only controls me sometimes. It’ss been there my whole life though. Taunting me with morbid nightmares and visions from a very very young age. Leading me to suicide attempts. Making me see and hear things that aren’t there. I’m not schizophrenic I know that for sure because I am aware my hallucinations aren’t real. They just grip me with fear. Ice cold raw terror. I’ve taken ketamine and mushrooms and have seen the figure inside my head as well. I’m unsure if he is real while I am sober however. He hates when I am at a worship night and tells me to kill myself or to hurt people which I have no intention of the latter. I have diagnosed depression and anxiety but nothing else. I am medicated and seeing a therapist. Any help or thoughts?