one cat going crazy

Question
When my now husband and i got together he had 3 cats. One was his ex girlfriends. She left her with him so she could find a place to live and was supposed to come back for her. Well come to find out she had moved to Kansas and never did. In that time we got another cat. This has been almost 3 years ago that the cats original owner left. She had a litter of kittens prior to that. One of our cats is from that litter. About 1 1/2 years ago we were living in an apartment that had a mold issue me and the cat(Momma) both got sick and she went crazy. She was attacking us for walking into our room, hissing and growling and pouncing my throat and she freaked out on my dad and shredded the skin on his leg. We moved and she was fine after that, now all of the sudden 2 days ago the cat from her litter (Nosespot)had got shut in a room when my husband went to let her out Momma freaked out attacked him and Nosespot and was acting crazy again. She was okay yesterday day but when he went back in the room to check on Nosespot (she wont come out now because Momma scared her) she went crazy again attacked him and our other 2 cats this time (she scratched the littlest one in the eye) and spent the entire night stalking us and hissing and attacking us for moving. I cant even walk through my house without becoming prey. Why is she doing this and how do I make it stop. We have 3 kids that stay with us every weekend ( my siblings)and my husband says if she doesn't stop this we will have to get rid of her. I love her ( and so does he), and I don't want to abandon her, that has already happened to her once but i don't what to do to help her.

Answer
Hi Ashley.  I'm not sure what could have triggered her behavior.  It would really be best to start with a vet visit, since a sudden change in personality is often brought on by an illness.  A fever or a toothache can make a cat awfully cranky.  High thyroid is especially known for making a cat snappy.  In this case, treating her as the vet prescribes would probably solve the problem quickly.

In the meantime, it would be safest for everyone to try to get her isolated to one small, dimly lit room and keep her there until she calms down.  Small spaces and dim lights are soothing to cats.  Try to make it a place where there's no traffic, if possible, where the kids won't be exposed to her, and she won't be able to see the other cats.  Just allow her a few days to relax, or even a couple of weeks.  Could be she just needs some time to unwind.

I would also recommend a product called Feliway.  It's a little expensive.  But I use the plug-in diffuser in my house to help with this sort of aggression.  You can learn more at www.feliway.com and buy it at pet stores, online or at some vet offices.