addiction is a general term that can pertain to anything from sex (nymphomania) to cocktail parties (socialclimania)... i believe that there can be a sort of genetic predisposition towards a general addiction and the individual fills in the blank from there with their specific choice of addicting behavior...

whereas with addiction to a manmade drug is a specific addiction caused by tolerance and dendency stimuli that occurs after an initial consumption (IE not connected with genetic predisposition)...

you layed out the groundwork of a specific addiction as opposed to the general form of predisposition (which i am will to sanction as having genetic connotations)... THAT is the differance