Can you be Addicted to Porn

Is it like a Drug?

My friend announced to me that he is addicted to porn./ He downloads it off the net he surfs porn sites and buys magazines. Normal people would say, most guys like to watch /buy or look at porn. I'd generally agree with that statement as there are very few guys who would not look at porn especially if its for free.

The part that concerns me is the guy is happily married and has a robust sex life. SO why would he be so hooked on porn. Mind you his wife doesn't know he does all of this. Now don't get me wrong I'm married and if its there even I would look at porn, but he says he's addicted, like a drug. He can't seem to stop or get enough.

Now I ask you is it all in his mind or can you be addicted. I have told him he's just a sleaze and he just needs to stop, but I think the problem is deeper. Any thoughts pon the matter?