I bought inside for our 3 year old male devon rex who has spent the last year struggling with the addition of another kitty in our house. We had tried feliway diffusers to help his mood and behaviour to no effect and were hoping that in time he would go back to his old happy boy self. Anyway he's been having inside out for around 2 weeks now and the change is astounding, he's less aggressive, more cuddly, seems brighter with more energy, playing more, basically on his way back to his old ways. So yeah, we're very happy, we love him so much and to see him sad was quite painful. I'm writing this for anyone who might be experiencing the same dynamic. Give it a try!