But, as I've said before on this website, if anyone wants to understand "dope culture" and the various aspects of it, can't do better than Trainspotting (1996) IMO. The concepts explored in that movie as they relate to opiate addiction (like using drugs to escape "existential pain", a constant struggle to avoid being "sick", polydrug (ab)use, personal relationships becoming transactional, etc) are universal across opiate-abusing subcultures IMO
And it's all packaged in a really well-executed black comedy, with an (IMO) ambiguous ending I really like.
Admittedly many other opiate-related films explore similar ground...but IMO Trainspotting explored all the ugliness of drug abuse and associated mayhem in an honest way, while replacing the "drugs are bad, mmkay?" moralistic subtext of certain films like Requiem For A Dream with the cynical-yet-humanistic perspective of the main character.