This is a really tricky problem and I’m frankly unqualified to answer it but I have done some research on it. I think you will find that your veterinarian is not particularly well qualified to answer the question either. However I would suggest that you get your veterinarian involved to check whether it is a physical or mental issue. It could be caused by a little understood condition called feline hyperesthesia syndrome. This is a mental health issue in line with other OCD type issues such as Pica. A cat may be predisposed to it. There may be genetic inheritance issues and there may be stress and environmental issues. Some veterinarians will prescribe mind altering drugs to change your cat’s behaviour. I don’t like these but they may be a last resort. I think the best possible solution is to really work hard on making the environment for your cat as natural as possible. This condition may affect indoor cats more than outdoor-indoor cats and if so it hints at the environment being a possible cause. Plenty of play, plenty of vertical spaces, plenty of windows for a cat to look out of so they can see prey items outside in the garden and routines which satisfy your cat’s natural behaviour. The best solution is the natural one and it should start therefore with the environment. One of the great weaknesses of the human-cat relationship is that they live in an almost exclusively human environment. Not many cat owners truly modify their environment to suit their cat. There are some exceptional instances where it has happened and I admire these people tremendously but the average home is a home for humans and the cat fits in and sometimes they can’t and they become mentally disturbed.