None of the above. Now it's pretty much all of the above. Maybe I should try heroin again. For science! Edit: Seriously though, at that time I also tried/used

None of the above. Now it's pretty much all of the above. Maybe I should try heroin again. For science! Edit: Seriously though, at that time I also tried/used a number of other substances and none of them were anywhere remotely close in the terms of "needing to get another fix soon". Edit2: I subscribe to the idea that it's largely individual. I might be a lazy enough person that the calmness of heroin speaks to me, while I can keep my distance to coke or amphetamines? Or some explanation beyond that. In reality the interplay is likely a lot more complex than that.