gambling addiction is pretty much accepted as an addiction. It has about the same impulse-control issues and instant gratification loop dependency as displayed by IM/email/gaming/forums "dopamine junkies".

Cigarettes also considered an addiction. I smoked from 1992 to 2002. I have never felt a cigarette craving as strong as those impulses to check email, this HN forum, etc... I quit smoking yet i'm pretty much slave to the internet communication habit and fighting hard to control it.