When I had no/low tolerance to benzos, they would work very well in curing my speed comedowns and allowing me to sleep. But like Sweet P said, once you get a tolerance from daily use they don't work like they used to, and really only remove some of the comedown related anxiety.
I used to love coming home from work after a day taking dexies and have some oxycodone along with some benzos and that would generally do the trick, usually smoking weed too.
These days I usually drink some alcohol, take some benzos then take some seroquel. It isn't healthy but when your aim is sleep I'll go to great lengths. I'm taking a break from my usual heavy weed smoking currently so that isn't an option for the comedown atm.
I'm coming down off 40mg d-amp right now and have had 4 beers and 30mg diazepam, all it's done is relaxed me somewhat but it hasn't made sleep possible. For that I'll take 100 - 150mg seroquel when I feel like knocking myself out.
To answer the question in short; benzos, opiates, weed, alcohol, sedating anti-psychotics all help to varying degrees.
