Best movies about drug addiction/life style

Christiane F. (1981)

Bringing out the dead

"Haven't used IMDB since 19th Feb 2017"

The Wolf on Wall Street (2013)
Fear and Loathing in Las Vegas (1998)
White Girl (2016)

Traffic and Rush haven't been mentioned yet... Traffic especially was quite good also The Wire if you include TV series

The Salton Sea (2002)

"For the people who don't do drugs, or just do them occasionally, it's something that becomes your life, and you belong. You finally hit bottom and you know who you are, because you can't go any lower. When you find... a friendship that you wouldn't have found anywhere else. Still and all, there's a kind of intimacy with those that can go the distance. Sometimes you see the world so clearly... and you know just what to do, and just when to do it. Just what you should've done, and when you should've done it."

Well, Leaving Las Vegas is an obvious one, if you count alcohol as a drug, which i do.

And, if you wanna laugh your ass off, i recommend "Withnail & I" (1987)

I saw it a few months ago for the first time and rewatched it 3 times since. It has so many great scenes and quotes.

Fear and Loathing. It gives you both a fear/appreciation of drugs and fun to watch

Fuck IMDB

Requiem for a Dream and Trainspotting.