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Is my cat's sudden aggression, mood swings, and tail flicking FHS?

Updated On September 23rd, 2025

Pet's info: Cat | American Shorthair | Female | spayed | 1 year and 1 month old | 9 lbs

I have a cat that is showing signs of FHS, tail swishing/flicking, terrible mood swings with no reasons for it, tail chasing, tail and neck grooming(excessive). She will be very nice one moment then out of no where attack viciously like she wants to kill you and it's not playful at all. I just wanted to know your thoughts. Thanks

1 Answer

Most Helpful Answer

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Answered By Dr. Melanie, BVSc MS

Veterinarian

Published on February 8th, 2017

From your description, it does sound like Ashildr could be suffering from FHS. Other causes of this behavior could include brain tumors (unlikely in a young cat), brain infection, or exposure to toxins among other causes. I would have her seen by the vet. Using on her history and symptoms, and tests such as blood tests, urinalysis, and possibly x-rays, the vet can rule out the causes I mentioned above in order to diagnose if she does have FHS or not. If she does, the vet can prescribe medication to help with her symptoms, such as anti-depressants.

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