Aw, I wouldn't say it's a blackhole. We definitely know a lot more about Reid's background than anybody else's. I always assumed that he got off the drugs soon after Gideon left - before Rossi got there, I think. He was a lot more ~himself in 3x06. The ~inconsistency~ that bothers me with Reid is his timeline - I really want to know how much time passed between "Revelations" and "Fear and Loathing", erk.

Also, further spoilers about Reid's secret have kind of pulled away from the drug addiction. :X I wouldn't be surprised if it was mentioned again, but I don't think that's his secret.