Could possibly be the puppy stage, but to me, sounds like separation anxiety. When we adopted Honeygirl, she suffered from sepration anxiety. Her anxiety resulted in eaten shoes, chewed up cardboard boxes, etc., and that was only the small stuff! Her anxiety also resulted in over $4000 in damage to our apartment and she scratched and scratched at the solid oak door and chewed up some carpteing. If he is crate trained, I highly suggest you keep him crated while gone. If it is separation anxiety, you need to work with him, by gradually working him up to being home alone. For example, begin by putting on your coat or shoes and picking up your keys to make him think you are leaving, then take them off and go about your business. Do this many times as you want him to learn that you putting on your shoes for example isn't a clue that you are leaving. Then, starting leaving him in very small spurts to begin with like leaving for 1 minute, then 2 minutes, then 5 minutes..... 1/2 hour, 1 hour, etc. You don't need to actually go anywhere besides out the door then then wait a certain amount of time and then go in so he gradually learns that when you leave, you will come back. Also setting a routine for every time you leave the house might help too, for example, telling him to watch the house, he gets a certain toy every time you leave, etc.

Separation anxiety can be very difficult to overcome and is very trying and difficult. It took over a year to break Honeygirl of her separation anxiety. We tried everything imaginable: drugs, scent deterrents, treats but nothing worked. She eventually got use to us leaving and being home alone for a while. However, she does still have episodes, especially if left in a different house than our own, like at my dad's.

Just incase anyone is wondering - we did attempt to crate train Honeygirl, but being that we adopted her at approximately 3 years old and knew nothing of her history, the crate stressed her out emensly and I thought she was going to hurt herself in the crate when trying to escape.

Hope this helps!