I'd suggest trying what QueenScoopalot and Jessika suggested since fleas, food, or even stress are the most common reasons for them to rip their hair out. MC, my male belonged to my brother originally. We got him about 3 years ago when my brother called and said he couldn't take him, could I. I agreed, went up to LA and picked him up. My brother neglected to mention I was getting a half bald cat. (He normally has a long coat). We had him vet checked and after a bit they finally determined it was probably stress and a habit. (My brother left him alone a lot and he's a very social cat) I gave him a lion cut, not only to even out his fur, but it was also now short enough he couldn't grab anything which allowed the skin which was irritated from him ripping the fur out to relax. Sure enough as soon as his fur was long enough he started ripping it out again. Back to the groomers. For about a year every time the fur got long enough he'd start to rip it out so I just kept him with a lion cut trying to break the habit. After about a year I was able to let his coat get a little longer, but any sort of stress (he's extremely sensative) he'd start ripping it out. It took almost 2 years before I could let his full coat grow in without him ripping it out.