I pick when I am bored (usually my neck) and when I am anxious (my scalp). It really is such a strong compulsion, and sometimes you don't even realize you're doing it until you snap out of it or someone asks you what it is you're doing.

I do think it can get to a point of being controlled. I've learned it's really about finding ways to make your compulsion direct towards something else. Instead of picking (sometimes I am not free of it) I have gotten into strumming a guitar, even though it sounds awful musically e_e for me it's a need to keep my hands as busy as possible.