Can Dementia/Alzheimers make a person mean?

This is a hard journey for my mother, but it has been equally hard for me. My mother has always had a mean streak, so now that she has dementia how do I differenciate between her old "mean" streak, and is this something she can't help now?
Trying now to just accept it all as part of her dementia. It's easier for me to cope when I think she can't help herself. I can be more patient and forgiving, even though at times I just have to leave rather than take her abuse. One thing that seems to be working in my favor is to just act like it never happened the next time we communicate. If I call with a pleasant voice, and demeanor, most of the time now it's as if it never happened. Does she even remember it happened? or does she remember and is just relieved that I'm letting her off the hook? I've come to believe it doesn't matter at all.
My life is easier if I just act like everything is fine, and I'm trying to take care of me.

Since your mom has dementia, I personally, wouldn't consider it possible to try to make her sweet, kind or easy to get along with. It's just not feasible. Their brain is not working properly, so trying to reason or create some kind of guilt in her is not likely to work. Even if it did work momentarily, she would likely forget about it and the lesson be lost. Therefore, I think that accepting the behavior as an illness and part of her disease is reasonable. Most people with dementia become difficult, resistant, and trying at times. I don't consider it a character flaw, but brain damage.

my mom who is 90 and living with us has started taking things from our house and hiding in her room, when found she denies it, acts so innocent and then becomes very mean. I make her sit in her room for awhile until she calms down and then I explain if she wants or needs something to please let me know not to just take it leaving me on a search hunt for what is missing. So far seems to work for me. Good luck

This is one of the best articles on here ever;;;;;;

https://www.agingcare.com/articles/bad-behavior-by-elderly-parents-138673.htm

Yes ...MEAN.....can be on their daily checklist.....followed by .....angelic..."who, me"?........flashes of innocence....and denial. Mean spiritedness can become a new hobby.

The best way to handle it is to take care of your own spiritual and health needs as well as theirs.......a sense of humor......a THICK skin......and a daily visit to this forum to reinforce the theory that you are not alone and it is NOT your fault!!!