She had always thought very highly of herself and would not believe most of what other people say, and it gets worse as she becomes older. When she meets problems, for example she can't find something, she assumes I stole it, when she gets stomachaches, she thinks my father has poisoned her, she even thinks her neighbor is stalking her, and trying to harm her whenever she lets her guard down, and after she moves to another place the same thing happened with the new neighbor. It's always someone out there being jealous of her and try to hurt her. I tried my best to reason with her and told her to visit a doctor but she wouldn't listen. She believes she understands herself better than any doctor. I just don't know what to do anymore and am afraid of her becoming completely insane. I am only 18 and feel very stressed out living with her. She grew up in a poor family, didn't receive proper care from her parents, and had to work very hard to make ends meet if that helps in understanding her condition.
Many situations can cause confusion.
Call her doctor to discuss it.
Call mom's doctor and tell her/him your observations.
If mom doesn't have a doctor, call your local branch of NAMI and ask for their guidance. https://www.nami.org/Home
Most importantly, you need to take care of you. We have a wise poster here named Beatty who says "There will be no solution while YOU are the solution.
The best hope for mom to get help is for you to start your life, your education and start a productive career. Mom's problems will become apparent to others and hopefully, she will be forced to get help.
I know you mentioned your Mom rather not go to her doctor, but in this matter you can use what is called "therapeutic fib".... you can tell your Mom that she would lose her heath insurance if she doesn't go to her primary doctor at least twice a year.... yes, it a fib, but if it works, that is great.
It might be that there is some sort of narcissistic, paranoid personality disorder.
it could also be menopause. Hormones imbalance can effect brain function too.
She's 94 now with advanced dementia and back in my life completely for the past 10 years. I'm an only 'child'. She lives in a Memory Care Assisted Living place and now takes plenty of anti depressants, but nothing works.
You can't fix this, just like I couldn't fix my mother. THEY have to WANT to fix THEMSELVES and some mental illnesses prevent them from even recognizing the fact they're sick.
The best answer is to remove yourself from the lunacy. ASAP. It's not that you don't 'love' your mother; it's that you love YOURSELF more.
It's okay to take care of YOU. And hopefully, she will take care of HER.
Good luck