The most common behavior problem of cats is inappropriate elimination. It is the cause of owners taking drastic measures including banning the cat to the outdoors, abandonment, surrender to a shelter, and euthanasia. Most inappropriate elimination is driven by a behavior disorder, however here is almost always something that initiates the problem. Sometimes it begins with a stress-producing or insecurity-producing event. We need to try to find the initial event and deal with this one step at a time.
Some underlying medical issues that can cause inappropriate elimination are cystitis or inflammation of the bladder, pain (arthritis, lumbar pain, etc), polyuria or frequent urination (renal disease, hyperthyroid, or diabetes), a very sick cat, or impacted anal glands. If you think your cat may be exhibiting any of these signs, they should be checked out by a veterinarian so we can try and solve the underlying issue before it becomes a larger problem.
Some cats may also have issues with their litter box. Cats can be very specific when it comes to litter, most cats respond better to clumping, unscented litter. You may also need to buy a larger box for your feline. The amount of litter boxes in the house can also make a big difference. The rule for litter boxes is that you should have one litter box for each cat you have, plus one! Some cats may also need to have an uncovered or covered box if they like more privacy. Location can also be important and some cats may need to have a litter box on different levels of the house or in different areas of the house. Cats also can start to eliminate outside the box if the box is not cleaned frequently, sometimes even some cats will need it cleaned every day.
Household issues can also play a part in inappropriate elimination. Feliway sprays or diffusers around the house may help if your cat is stressed or becomes territorial, there are infused with pheromones. If there are already spots of urine in the house you may need to replace the carpet or get it cleaned to get the scent of urine out or they may keep marking in that same spot. A 50/50 mix of an enzymatic cleaner with water can be injected into the carpet pad to help with the scent.
The behavior aspect of inappropriate elimination can start if there is a big change such as renovations on a house, moving, or adding multiple animals or family members. It can also happen if things in the house are taken away or rearranged. Medications can also be used to help with inappropriate elimination such as Buspirone, Clomicalm, and Fluoxetine.
The prognosis for inappropriate elimination is good if the issues have been going on for less than 1 month but if it has been present for more than 6 months the prognosis is poor but not unfix-able. It may take time to correct the behavior and sometimes even subtle changes can make a big difference but you should rule out any medical conditions first, then go to any behavior issues and approach everything a step at a time.