Gradually shorten the length of time the cat is outside until you no longer let him or her out at all, with the exception of the times that you and your cat go on walks together. Cats really do need human companionship to be happiest, and when they spend all their time out of doors, they get very little attention. An outdoor cat may welcome the indoors if he or she gets more love, attention, and play. Provide plenty of things to keep your cat occupied indoors such as secure cat furniture which offer acceptable and interesting places for your cat to lounge, play and scratch, and hopefully be able to look out a window. You should also provide scratching posts, corrugated cardboard or sisal rope for your cat to scratch and be sure to praise your cat for using them.
Cats also love toys of all varieties, and some also enjoy fresh greens.
You can buy kits that include containers and seeds to grow, or plant pesticide-free alfalfa, grass, bird seed, or catnip in your own container. I f, after all these efforts, your cat remains stubbornly committed to life outdoors, help him or her adjust by providing an outdoor covered enclosure or run that the cat can access through a window or pet door. Such a facility gives the cat some of the advantages of being outside while minimizing the dangers. You can make the outdoor enclosure interesting and appealing by adding objects for the cat to explore, such as tree limbs, multilevel cat condos, tires, toys hanging from branches, and boxes in which the cat can curl up or hide. Remember, when cats become a nuisance, it is the cat's owners who are at fault.