What condition is extreme paranoia a symptom of?

My client insists she has all her mental capacities but tells me the most ridiculous things that her family is doing to her. She's 89 but she thinks her grandson comes into her adjoining home in the wee hours of the morning to eat her food and one morning at 5:30 brought two men in to see her (one of which, sold her her hearing aid). She is always telling me weird stuff her family did to her.

I worked with the elderly for three years and this sounds like Alzheimers or dementia. Some medication can cause things like this and with the elderly it is difficult. When it is just beginning it is difficult. I had a lady who thought someone was peeking in her windows and someone eating her food out of the fridg. She would cover her food with towels and wrap to keep them from eating it. She lost things in the house and swore someone stole it. This will only get worse. She may eventually have to be assessed to see if she has capacity to make her own decisions and be appointed a guardian to care for her.

There are a lot of disorders that do that, but it sounds like dementia (alzheimers) to me.

It could also be schizophrenia, bipolar disorder, psychotic depression, post-traumatic stress disorder or paranoid personality disorder. I maybe left some things off there.

It does sound like she is having trouble with her memory and possibly mentation. People who can't remember what's been going on around them, like the fact they've eaten all of their favorite cookies and haven't been to the store to replace them, or don't remember buying a new appliance in the last few months, will sometimes make up (and actually believe) fantastic stories about how the cookies disappeared or the appliance appeared.
You should have her evaluated by someone who has experience with Alzheimer's and other neurological conditions.

have you ever considered she may be telling the truth,maby her grandson is coming in and eating her food,and baby his Friends are hard up and need money,maby someone else is missing a hearing aid,if it sounds like she is being abused you should call adult protective,so they can look into this matter.i meen its not that far fetched that her grandson may be coming in and eating her food.it doesn't sound to weird to me.

If she's 89, it's most likely dementia (progressive loss of cognition) or delirium (temporary confusion).

My mother said strange stuff when she got dementia. My aunt died a few months ago and she used to tell stories about "handsome young men" who came to sing songs and dance with her. My other aunt died in 2001; she once said she was in a swimming pool with Jay Leno.