Feline dementia -- formally known as feline cognitive dysfunction -- doesn't cause death, but it can affect a cat's quality of life to the point that you must consider euthanization. As it does in humans, dementia generally occurs in older cats, who might simultaneously suffer from other health issues common in elderly felines. It can take several years before the early signs of feline dementia give way to a cognitive decline that truly interferes with your cat's quality of life.
Feline Cognitive Dysfunction
By the time a cat reaches the age of 16 -- very old age for a feline -- he has an 80 percent chance of suffering from feline cognitive dysfunction, according to the ASPCA. Signs of FCD can start years earlier, with more than half of cats age 11 to 15 showing signs. If your older cat starts having elimination accidents in the house, appears disoriented, stops grooming himself, exhibits personality changes and starts displaying aggression toward you or other pets, take him to the veterinarian for a diagnosis. Your vet can prescribe medication to help alleviate certain symptoms and may suggest dietary changes to aid cognition. Your vet can advise whether your cat has deteriorated mentally to the point where euthanasia might be the kindest option.