Can a cat have mental illness?

[PoolPlayrChick]

About 9 mos ago a Berman looking kitten found his way in our backyard, we only knew he was there because he hide and meow really loud. We would call for him but he wouldn't show his face, till bout a week later he poked his head out from under the spa. He has the prettiest blue eyes, all white with light gray on ears, feet and tail. I understand him being afraid not knowing people evidently, but he was brave enough to enter the house at night thru the sliding glass door that is kept open wide enough for our other cats to come and go.  I found him lying in the dogs bed, and he would eat the dogs food.  The dog never really saw him and was at the end of his life and had to be put to sleep a week later. Well the kitten we named Casper, would hide out in the living room and we fed him there and I gave him some toys to play with, he would act interested, but would only play with them when he was alone. (you could hear the bell) then he got brave and would come into to me and my boyfriends room and hung out there for a few weeks, playing and being loving, but not totally relaxed.  He one day sprayed my boyfriend in the face while he was sleeping, needless to say he was yelled at and he ran away.  Well that was the last he came into our room, he then moved into our roommates room to sleep. I still pet him and he would come lay on the couch by where I work and talk to me. He would disappear for a couple days but then comes back. He will let you pet him if he is laying down and he loves to be brushed.. but show him one of his toys and he freaks out.. and when he is out in the kitchen area or wanting to come in he will meow lots and loud, we talk to him and he talks back but approaching him he splits out the door and looks back all scared.  When he eats the cat food and someone comes into view he freaks out and splits. He is getting more and more paranoid. He doesn't fight or isn't afraid of the other cats a male and female who fight each other. The female is like casper a feral cat that moved into the back yard about 5 yrs ago, she has never had babies that we know of and she hisses at everyone.. well up until two months ago, she only came in the house to eat.  Now she decided to move in and even slept in our beds a few times, she is loving, but she will claw, hiss and bite if she feels threatened.  She even plays with the toys. But, Casper is the concern. Could he be mentally ill or retarded?

[Savas]

Well, it is possible. Cats, like people, are susceptible to similar conditions.

The problem is defining what "mental illness" is; clinically diagnosable disorder that significantly interferes with an individual’s cognitive, emotional or social abilities.

Cats are creatures of very structured social behavior. It sounds like you have a cat that was either abused, or has a low threshold for stress and was subjected to treatment that may have been mildly abusive but due to such a low threshold for stress was psychically wounded by that treatment.

It may also have been deprived very early of association with other cats (including it's mother). This would have left him in the position of not being able to learn what would be acceptable social behavior in the cat world.

The spraying incident, for example;

One explanation is Casper was trying to express feelings of possessiveness and affection towards your boyfriend. But due to a lack of social training, went about it in a very unpleasant and unfortunate way.

Another possibility is he suffered a "stress incident". If he was "locked" in the bedroom with you, for example, he may have suffered a sudden stress reaction from a feeling of powerlessness at being stuck in an enviornment with with creatures (the two of you) he is intimidated by.
His reaction was an attempt at "empowerment". But spraying, he was marking and laying claim to the alpha male (your boyfriend) and attempting to reduce the threat (in his mind).

So... I wouldn't call him mentally ill, just socially maladjusted. The problem is you have to try to see how Casper see the world, and then adjust your behavior accordingly to reduce what he appears as threat to keep his stress levels down.

Allowing such a cat to coexist with you is a difficult and noble thing to do. It's not dissimilar to adopting a severly  autistic child.  

There will be difficulties that arise, but you'll find if you have time and patience, you'll see signs that show he appreciates and loves you in his own way.