Operation has made my cat scared and timid

My very fun and excitable cat got a piece of grass stuck in his throat and, last week, went under general anaesthetic for a minor operation to remove it.

He has come back a totally different cat - he is scared, won't sit on our lap, won't come when called (he used to, believe it or not!) and looks like he's constantly ready to leg it.

Has anyone else had this? Any ideas??

Sometimes cats have prolonged behavioral changes due to the anesthetic. Was ketamine used to induce anesthesia? If you do some research, you'll find there are isolated cases of neurotic behavior following ketamine usage, even after it's washed out of the system. Ketamine causes hallucinations, and the cat may have lingering psychological distress. The good news is that it wears off eventually, but it could take some time. Months, perhaps. Meanwhile, just treat him with extra TLC.

If you notice anything that could be physical or neurological problems, or if the behavior seems to be getting worse, then please get in touch with your vet.