There is no evidence that some people are more or less susceptible to "addiction," in the sense you use the word, than others. There is a shit load of evidence that people's circumstances make certain activities (using opioids, self medicating with tobacco, drinking too much, etc. etc.) more or less useful, accessible or desirable than other activities. Very, very, very (VERY) few people have truly what you call an "addictive personality," in any case, when the resources to live a healthy life are readily, actually available and supported/endorsed by their society. To the degree you have more or less people with said addictive personality, or to the degree that certain people are deemed as having such a "personality," that is much more telling about the society they live in than anything about them whatsoever, especially when it's the intrinsic characteristics that are most important.
I'm curious 2Iso, are you a "heroin addict?" Ever been one? I mean because I know of a handful of people in this thread who you'd probably refer to as or think of as being heroin addicts. Especially with your comment on how people aren't being more sympathetic to "heroin addicts," it's almost ironic.