ETard
noun (rhymes with Retard).

Someone who has compromised their cognitive function by using too much "E" or ecstasy (MDMA).  Common expressions of being an ETARD are diminished short term and long term memory, merciless bouts of depression, crying jags that last longer than a day, finding enjoyment in watching a blank TV screen; at it's worst, thinking Britney Spears isn't really that bad.
You do NOT want to go out with Bob, he raved so hard in his teens he's an ETARD now.

Crap, dude, stay away from that bitch, she's an etard.

We rolled so hard we wound up etards.