Not all declawed cats develop behavioral problems but there seems to be a big relation between declawing and some different behavioral problems they would not develop otherwise. I dont want to start a debate about it, its just something I’ve come across and would not promote doing. Examples of why are on this site (and others): http://www.declawing.com/htmls/declawing.htm
“Others, deprived of their primary means of defense, become nervous, fearful, and/or aggressive, often resorting to their only remaining means of defense, their teeth. In some cases, when declawed cats use the litterbox after surgery, their feet are so tender they associate their new pain with the box…permanently, resulting in a life-long adversion to using the litter box. Other declawed cats that can no longer mark with their claws, they mark with urine instead resulting in inappropriate elimination problems, which in many cases, results in relinquishment of the cats to shelters and ultimately euthanasia”