Signs of Chronic Stress
Cats show chronic stress in many ways: decreased grooming, decreased social interaction (more frequent hiding), excessive vocalization, decreased exploration or play, less sleep (she's too busy staying attuned to threatening surroundings), withdrawal, changes in appetite, inappropriate elimination. Since many of these behaviors can also indicate illness, it's important to take your cat to the veterinarian to rule out possible health problems.

Sources of Feline Stress.

Environmental: A strange animal lurking in the  yard,  scary noises (such as construction work or a  hostile  owner yelling), new baby or new pet, strong    scents (air freshener, colognes or dirty litter box in  multi-cat homes), blaring music or television, or a  house full of company.

Physical: Illness, obesity, physical trauma, punishment by owner, fleas and other parasites, unpredictable feeding schedule (cat goes hungry for extended periods), or surgical procedures.

Emotional: Neglect, death, or a prolonged absence of human or animal companion in the home, lack of mental stimulation (such as challenging play), or lack of choices or control over a situation (such as only one feeding/litter station in a multi-cat household). Coping Your cat requires places to hide from perceived threats or bully cats in your home.

Vertical shelves, boxes, and cat trees work great. Offer therapeutic outlets, like a scratching post, heated bed or pad, or sunny window perch. However, if a strange cat lurks outdoors, you may need to close the shades temporarily.

Make sure each cat, in multi-cat homes, has her own feeding and litter station and keep them very clean. If you have a kitten, expose her to many different situations, people, and pets to help her handle stress better as an adult.

Try a pheromone or herbal therapy, such as Feliway or Rescue Remedy. Interact with your cat often; give her daily attention, interactive play, and petting. When you stroke her, her purring also helps relieve stress.