i also abuse dxm...honestly i have done everything and quit everything but weed and my occasional bout with 'godjuice' as i called it before i found pills. it freaks my shrink out, but i am bipolar 2 and i have found that when down, at high doses, it's like a temporary manic episode, and at low doses, like 100-200mg it can cure depression, for a time, in like an hour.
i have done this just through total experimentation..trial and error. my shrink is about to send me off to treatment (sorry, i need my bud. harm reduction is the only thing that makes any sense at all..) but far as i'm concerned i am just gonna keep what i have been doing for some years now.
at high doses, it can really mess you up, especially if you BINGE on it..