Relentless tail chasing and digging up the carpet, please help!!!

[SamTheDog]

Hey everyone,

My dog Sam (just about 1 year old) is having some major issues. In the past 2 months he has started chasing his tail relentlessly. He also, usually when someone comes over and he gets excited, he will stare at the carpet as if he sees something and then starts to try to dig it up. He will do this for a good 15 minutes, and then randomly throughout the rest of the day. Most of the time he acts perfectly normal. But when he starts into these two behaviors, almost nothing can take his focus away from it. Ive tried treats, toys, even grabbing his face and making him look at me, he will fight you just so he can avert his eyes back to the carpet and keep digging. He will sit on his tail and grab it between his legs. When he chases his tail its like you arent even in the room. When people come over, dogs are usually all about the new person in the room, Sam just immediately starts chasing his tail and staring at the carpet and digs. Ive read all about trying to divert his attention so break the habit but he just just relentless. Yes he has been to the vet, they found no physical reason why he would be chasing his tail, he doesnt have any rear end problems. What is wrong with my pups brain and is there anything I can do? Medication? Some sort of training? I think he has a screw loose and I am afraid there is nothing I can do, please help.

-Matt

[JeanKBBMMMAAN]

Relentless tail chasing, staring at the carpet, digging the carpet