I dislike these kinds of generalizations (I think I’m especially allergic to words like “all” in these kinds of statements.), but Russell Brand has put his finger on something here:
All addicts, regardless of the substance or their social status share a consistent and obvious symptom; they’re not quite present when you talk to them. They communicate to you through a barely discernible but un-ignorable veil. Whether a homeless smack head troubling you for 50p for a cup of tea or a coked-up, pinstriped exec foaming off about his “speedboat” there is a toxic aura that prevents connection. They have about them the air of elsewhere, that they’re looking through you to somewhere else they’d rather be. And of course they are.
Then again, isn’t this the nature of addiction? Craving or drug hunger is about being unable to ignore drug related stimuli in the environment or in their own mind. It’s not that different than anyone else feeling serious hunger pangs and trying to listen to an acquaintance while delicious smelling food is being served across the room. Or, trying to focus on a conversation while watching a bear over the shoulder of the other person.