Why won't you believe me?!
Your challenge is to create a character who is completely and utterly certifiable. In other words your character can no longer grasp the difference between what is reality and what is hallucination. Whether your character is in a mental institute or causing chaos in the street, or perhaps manages to hide the truth is up to you.Is your character really crazy? Or is the world menacingly unaware?
First or third person, that’s your decision (I trust you make the right one
Good luck, feel free to write mature stories.