Not a pet, but my mother has schizophrenia. She responds well to medication, and was dianosed two years before we got our mitred conure.
She was a stay at home mom, so although Pedro's favorite person was my dad, my mother was the one who was around Pedro the most. (Pedro was a she we found out later), She followed my mother around somewhat with routines and would normally perch beside my mother on the couch to remove her hair clips, once a mole haha, or perch on my mothers feet until my dad came home from work.
When I went away to college (I was 14 when we got Pedro), Pedro waited outside of my door for a everyday for a month, but eventually got over it, sort of. She was a biter when she got excited.
The medication my mother takes has taken it's toll on her nerves, she had to stop driving and her legs and feet started to shake. She felt nervous to have Pedro on her anymore. Then my mother had more and more problems for a few years. Pedro still hung out with my dad on the couch, but after these years, she started plucking. She finally plucked so badly that she only had wings and her pretty red and green head until her death at what we think was about 30 years. Interesting to see a bird fly without a tail.
The vet said she had a touch of arthritis, as when she preened, she would call out, then bite whoever she was on a second. When we started offering her medication for it, she would make a bee line for it in the mornings before making a stiff stretch. I think that started the plucking, but honestly, believe it was my mother's illness that affected Pedro the most.
I had a nice time with Pedro a few days before she died. My parents had to go away so I got to bird sit. She seemed very happy to see me and didn't do her normally attacks on me. She ate off of my plate, and played with some paper.
My parents came home, and she died two days later. My dad found her curled up behind a robe in the bathroom in the morning. (She liked to sleep on the shower curtain.)