That one was "Requiem for a Dream", directed by Darren Aronofsky, the same guy who did "Pi". Fear and Loathing was by Terry Gilliam, who also did Time Bandits, 12 Monkeys, and the Adventures of Baron Munchausen. I would put Permanent Midnight on the Requiem side more than the Fear and Loathing side--it's not crazy trippy like Fear and Loathing (also a fantabulous book by Hunter S. Thompson). But it's also not as gut wrenchingly bleak like Requiem.

note: I own all three of these movies on DVD and watch them pretty frequently, as well as Trainspotting. I love living vicariously through crazy drug movies.