Psychiatry & Psychology--General/Diagnosing my sister?
I will try to condense my sisters situation as much as possible.
Before - she seemed to live in a happy bubble. She lived up to an image of being kind and popular and a good girl. She could come across as a bit simple with inappropriate responses to jokes or conflict.
During - she was in a relationship with an older man and they had a child who is now 8. They were together for about 12 years but lived separate lives. He was incredibly self centred. About 5 years ago my sister started making accusations about him bugging the house and secretly invading her privacy. Most recently she said he was a criminal mastermind and a mob boss who was out to convince everyone she was crazy. She said he was going to kill himself and frame our dad for murder. I convinced her to come to my house but she got lost and was picked up by police hysterical saying that she hadn't killed "him". The relationship was over and she went to live with our parents.
Afterward - she lived with my parents for about a year. At first she was very meek and emotional but she soon started to become defiant. She is convinced that our dad is evil and possessed by a demon. She says that her son is not the real him and she needs to find him. She works as a dinner lady and has told colleagues that she sees ghosts. It became very hostile at home so she was very reluctantly moved into a neighbouring house but she refuses to furnish it and she goes to our parents house for most of her meals which still causes hostility but she will challenge them to kick her out and uses her son as blackmail. She will do the opposite of what anyone suggests to her. I saw her recently and I'd bought her a mild curry because she never liked spice but she accidentally took some of the ultra hot one and in spite of me pointing it out, she ate it anyway.
Diagnosis to date - depression. They have prescribed her an anti psychotic medication but she doesn't take it reliably. My parents attend appointments and say that she suddenly acts normal and puts some effort into her appearance.
I am hoping that you could suggest a possible diagnosis and any suggestions on how we could get her officially diagnosed which would enable us to insist on more support on her behalf. Everyone she has seen so far have come to the same conclusion in spite of one of them tricking her to admitting that she hears voices.
Because I'm in another field in another country, do not take my comments as authoritative but as coming from, say, a friend, neighbour, relative, ....
From what you describe, she sounds to me more somewhere between schizophrenic and personality disordered than depressed. With some types of this condition, symptoms come and go, and can be under some measure of control, making it hard to diagnose. Good written descriptive records can be helpful if the at-hand professional will accept them.
But diagnosis is one thing, management is another. Tricking her is, well, tricky because of the paranoia that typically accompanies her condition. Insisting on anything may meet with resistance from her and dismissal by the authorities. "Voices" can be an excuse or a ploy, or an auditory hallucination pointing to a psychosis.
I think your family could benefit from advice and resources from the mental-health community on how to handle this difficult situation, so that's where I would suggest you turn. Maybe a family doctor could point you. Perhaps a psychiatrist or a clinical psychologist. Or a clinical social worker.
Meanwhile, there's something you can try. Have a sit-down or a walk with her, assure that you know she's been through a lot of unfairness and that you'd like to try to make things smoother -- if she would let you know what she would like. (And, whether or not her reply goes off the rails, document it.)
I'm sorry I'm not in a position to offer more direct help, but I thank you for asking us and hope my comments will prove somewhat useful