Its definetly common for people to move onto another substance when they quit one. Or move on to anything that fills that void, be it food, sex, energy drinks, whatever. I know for me, I quit the alcohol and then everything else flaired up. I'd stay up too late and drink to much caffeine, just over do something else....

I was watching Intervention about 2 months ago when I was at a low point in my sobriety. Someone was smoking meth on the show. I've never done meth, but the thought went through my head "Now that looks good....." I freaked out and jumped back into doing what I do to stay sober.

So I know for me, yeah, I can replace substances with just about anything. I can over do just about anything. Its the nature of addiction.