cat pooping on carpet::For the last couple of months he has been pooping on the carpet in the living room cat pooping on carpet

cat pooping on carpet::For the last couple of months he has been pooping on the carpet in the living room.
She went to the vet and physically is totally ok.
The vet mentioned that it might be a mental thing with him.
Before this started happening she had no problems with him.
She bought another litter box and still he is pooping upstairs.
Nothing has changed in his routine, she tried different food and cat litter but so far no change.
This started out of the blue without apparent reason.
Does anybody have any suggestions before she gets rid off him?

http://leqorosyouswearingstyleblog.blogspot.com/2011/09/cat-pooping-on-carpetmy-daughter.html cat pooping on carpet::My daughter decided she was going to change the
cats diet and his litter box material cat pooping on carpet