If your cat begins to over-groom themselves, biting at their fur to the point of leaving bald or sore spots, it could be a sign of fleas, an allergic reaction, or a skin condition. However, this is also a classic feline response to stress, so if you spot it in combination with other symptoms, it's time to investigate further.
Like over-grooming, if your cat is scratching themselves constantly then this could be a simple sign of itchiness caused by a physical problem, or it could be a nervous reaction to emotional conflict.
Nervousness Around You
Although cats are generally happy in their own company, if your furry friend suddenly starts to take herself away from contact at every opportunity, finding secluded corners to hide in, then this is a clear sign that something in the wider world is troubling her and she's seeking escape.
If your cat simply can't seem to stay still and is constantly pacing around your home, often repetitively calling out at the same time, this probably indicates a sense of insecurity or worry that something isn't right in her surroundings.
Changes in Appetite
A sudden fall in appetite could be a sign of a stomach problem, or it could be nervous stress. Likewise, if your cat is always hungry, then this could be because of a problem with worms, or it could be the feline equivalent of comfort eating. Have her checked over medically to rule out physical causes as a first step.
Cats are famed for their ability to sleep at will, but if yours drastically changes her habits and rarely rouses herself from slumber, this could be a symptom of something deeper. While it's not likely that cats suffer from full-blown depression as humans understand it, a lack of energy can have mental as well as physical causes.
Of all the domesticated animals, cats are probably the closest to retaining their wild nature and even the most placid of kitties can be surprisingly vicious at times. However, if aggression seems to be becoming an increasing habit, it could be that your cat is feeling under threat and is fighting back in the only way she knows how. This is especially important if the aggression is towards humans, as it's a clear signal that the animal is losing perspective of her place in her social hierarchy.
What to Do Next
If you spot any of these signs and have ruled out any physical illness, try to think what might have changed in your cat's life recently to cause a breakout of stress. Has a new animal moved into the neighborhood? Has there been an increase in noise in the area, from building works in the street for example? Cats are creatures of habit and it doesn't take a lot of change to unsettle them.
However, if you can see no obvious changes that may have sparked off the stress reaction, your veterinary surgeon should be able to recommend a feline behavioral expert who can probe a little deeper and hopefully set your cat's world back on a level footing.