My family has a history of mental illness, I have/had two uncles, one of whom killed himself before I was born, the other has a restraining order against him keeping him away from most of our family.
I've had what I think are hallucinations for a long time. At night, I often believe there are faces outside my windows, looking at me, but I'm always too scared to look and make sure. During the day, I often see tiny things floating all around me, that look somewhat like the spots you get in your eyes when you've looked too long at a light.
Not long ago, I overheard my dad telling someone that he sometimes sees yellow lights floating in his eyes, which I think are the same thing I see, which makes me wonder if they might be real.
Some of my family members say that my uncle is schizophrenic, so it might run in my family, but I don't have much faith in the diagnosis, so I'm not sure if it helps you.