LuvDFuzz, welcome to Pet Talk! Reading about Scooby was just like me reading about my husband's cat Scooter. I can totally sympathize with your predicament! It almost sounds like the same kind of behavioral problem that my husband's cat has. I do agree with 4 feline at the possibility of the behavior occuring as a direct result of the declaw prodecure. I was startled to find out that behaviors such as these can develop after surgery. It is still a little unclear if it is a direct correlation between the surgery and behavior. I've read different articles and opinions from vets about this issue. Unfortunately, there really isn't a lot you can do but try to observe Scooby's behavior before attacks, so you can try to aviod them. Or, my vet recommended 2 different kinds of drugs for Scooter when we were trying to come up with alternatives. The first was to give valium. The benefits are it's cheap and it usually works. The downfalls is that you have to give it 2 times a day. We tried this. We definitely did notice that he relaxed considerably. Like your kitty, our Scooter is just a complete terror at the vet's to the point that they have to "net him" so that can tranquilize him before even touching him for an exam. The valium make him considerably more relaxed and friendly.
The other option was a drug called Ovaban. The plus sides of this were it works, it's affordable, you only had to give it once a week...I think. But, the downfalls was that there is a possibility of it causing a type of cancer in cats, that once you find out about it...it's too late. My vet did say it doesn't happen very often...but that doesn't mean much when it happens to your cat. My husband was a little leery of that choice...because knowing our luck...it would be our cat!!
Good luck with your kitty. I certainly hope you can get him to open up to you and not attack so much! Please keep us posted!!
*hugs*
Karen