In the past couple of weeks my constant companion of 13 years, Missy, has developed a problem that is unacceptable. Nothing in our household has changed. We have been and remain one human, one precious cat nor have we been visited by any other pets. Two weeks ago Missy started defecating on the carpet in the dining area at night. She didn't generally do it in the daytime but always at night except for one daytime incident. Her litterbox is in the laundry room as it has always been and it is clean. I use the same litter that she has always used. In an attempt to deter this new unacceptable behavior I sponged the carpet around the perimeter of the dining area with white vinegar and water. That didn't stop her. I then began providing an additional litter box in that area that I placed there when I retired for the night. All was fine, she didn't defecate on the carpet but used both the new litter box in the dining area and the regular one in the laundry area each night. I gradually moved the new litter box toward the laundry room door over the period of the week. Then last night I did not put the second litter box out and sure enough, she again defecated on the carpet. I'm at my wits end as to what to do to stop this behavior. As she did this once in the daytime when I was watching I know that she is assuming the regular position for bowel movement. She just did it deliberately. When I loudly said NO to her she ran into my bedroom and finished on the carpet in there. Has anyone else been through this type of thing? What did you do? What is the cause of this? HELP!