My persian had re-occuring cystitis and we spent a fortune on vets fees and tests to try to discover what was causing it. She was put on to cystaid which was a nightmare to get into her Then a young vet said I should try the Royal Canin food for persians as there was something in it that helped maintain a healthy urinary system. She was also an indoor cat, so it was suggested that if she wanted to go out perhaps we should let her. We went out and bought a cat flap and some food. She has never looked back. She stopped taking the cystaid years ago and hasn't had a single bout of cystitis I would definitely look at her diet, and also try to rule out any stress that may bring on an attack. I hope she gets better soon.