Cat Paranoia

For some reason my male cats behaviour has changed over the last several days. He didn't fear anything (not even the vacuum cleaner). Noise of any kind rarely bothered him. But now it seems he is scared by every little noise. He is now spending most of his time in the basement, when he does come upstairs or when I carry him upstairs, he looks around with extreme caution (its like he was put into a new surrounding),and he does not stay upstairs very long, he'll high tail it to the basement. I do remember running to the phone one evening and this really spooked him, he ran downstairs (the female also ran downstairs)but the male was the one who hid for the next hour or so. Several months ago Cujo went thru something that has yet to be diagnosed by numerous vets I took him to see. For about 3 months the cat would average anywhere from 1 - 3 hrs of sleep thru a 24 hr period, he was not interested in any kind of activity (he was disinterested in everything), his appetite decreased. He seemed to scared of his food dish. He also exhibited some of the timid and scared behaviour that he is exhibiting now. One of the vets attributed the scared behaviour to a drug that was given to him (bhutorphanol) which she said could act as a hallucinogenic. He has been off medication for many months now and he's been back to normal (behaviour) up until these last few days. Has anybody experienced anything remotely similar to this.

Well, something like a loud noise or experience can trigger something like this. They can act this way for a few weeks until they know it's safe again. When you say he's even scared of the food and such it worries me. Things like this can also indicate a serious illness. Did they do any blood work on him at the vet. Maybe check liver, kidneys and thyroid? How are his bathroom habits at the moment?