it's hard to stay out of the obsession with the addict isn't it?
i thought the same thing, with mine, and then when i knew he to be clean & sober, the picking seemed to happen still. he said it is a nervous habit. (yeah sure it is i thought)
then i did some google-ing and discovered that for some people it is. i know a guy who has never used drugs and does this, esp. when times are stressful. now i know my addict is doing it a lot the last few days, because he is getting ready for a major change.
so even though your gut is prob the best indication, sometimes our heads are spinning and we don't know which end is up. evaluate on his behavior. why is he getting ua's every 3 days? is he in a program?