What do I do when my mother is convinced someone is tormenting her and wants to do her harm?

My husband and I did live with my mom for about 6 months while we were moving. She did have episodes while we were there and when we could have moved into our home, we delayed the move by a few months because we were worried she wouldn't fare well when we left. We've been gone from her house for about four months now and I do believe the episodes are worsening but at the same time, she doesn't wants us living with her either. She's fiercely independent and won't acknowledge needing help for anything.

I'm assuming your mom has dementia/alzheimer's? Do you live with your mom?
Not sure if what I have to say will be of any help to you, but my mom has dementia and she does suffer paranoia as well. To be clear, she doesn't claim to hear any particular person or thing. However, she is convinced that people are peeping in her windows and she is convinced that these people mean to do her harm. I live with my mom and so I'm able to reassure her that I will deal with whatever and whoever and that she has nothing to worry about. Call me a poser, but I'm able to convince her that I'm a badass and will kick anyone's butt if they come near our windows. Just reassuring her that she's not alone and that I'm there to protect her helps her a great deal. I gave up a long time ago trying to tell her that she's imagining it though, because it"s useless. She doesn't believe me when I tell her no one is looking and she only gets upset with me for not believing in her.

Possibly it could be her medications, if she is taking any. You could do a "google" search of her medications, and see what the side effects are. In addition, you could have her tested for Vitamin B-12 deficiency.

I assume this behavior has been discussed with the doctor who is treating her dementia?

You can try to allay her fears by going outside and chasing him away, then telling her the neighbors and police are keeping an eye out. This may help for a while, but you might find the pest returns again in a few days. Imaginary enemies can be tough to deal with, like dealing with children who knows the boogeyman is under their bed every night.

She apparently has dementia or alzheimers, so shouldn't she be seen by a doctor? Maybe Namenda or Aricept would help? Or could it be being caused BY some sort of drug? Too many questions, and not enough answers I'm afraid.