Made a huge change in one day to my 20 pound formally stray ,verging on feral ,cat that I recently picked up. He was sick at first, but once feeling better he started attacking some of my other(8)cats. I really was to the point of thinking he would have to go back to his colony, but this shirt changed everything, in just one day. They all seem calmer, with the aggressive one not causing issues. I am hoping this continues. So much velcro- I do wish it was a little easier to get on. I would recommend trying this for any behavioral situation that you have going on. I do plan on getting at least one more, for one that is spraying . I think a lot of behavioral issues we come across stem from emotions, and this shirt , while not cheap, is definitely worth trying.