A beautiful jet black female cat adopted me 2 years ago from a cat charity. The previous owner only fed her dried food and knowing that wasn't healthy I put her on wet food that she loved as not having it before ( unless the charity fed her this). As a treat I started giving her Dreamies that became a sort of side dish to her wet food.
A few months later I noticed she was licking and chewing herself (no fleas or parisites) acting nervous and started getting bald patches all around her lower abdomen and legs. I was close to putting her in a carrier and taking her to the vet when I happened upon a post on a cat forum stating that cats that over groom are put on anti-anxiety medicine! In some cases 60 quid a month! After a bit more research I stopped the Dreamies and gave her healthy dry treats and after 6 to 7 weeks she's got 70% of her fur back. Hope this helps.