Oftentimes, your cat’s behavior problems are her way of communicating to you that she is experiencing a serious health issue. Any sudden change in your cat’s behavior that does not resolve itself quickly after an obvious cause (like last week’s visit by your sister and her brood of unruly kids) should be considered a potential medical problem, and your cat should be checked by your veterinarian.
Keep in mind that even behavior problems that reveal themselves more slowly also can be the result of a medical issue. For example, your older cat may become less tolerant of the other cats in your household because of a serious health concern, such as kidney disease. Your older cat may not want to appear weak in front of your other cats, so instead of playing and cuddling as she once did, your older cat becomes aggressive towards her feline roommates.
Additionally, behavior issues also can become medical problems. A cat who is fearful of another cat in the household may be too afraid to come out to eat an drink or may not feel safe going into the litter box. Not eating or drinking enough, or holding her bladder for long periods of time, can quickly become a medical problem.
Once you take your cat to a veterinarian and can rule out a medical condition, you can begin working with your cat to eliminate undesired behaviors.