If you’ve heard of ketamine, it’s probably because of its high level of consumption being a club drug. But it could also be one of the biggest breakthroughs in treating severe depression in years.Ketamine works like a flash mob, temporarily taking over a certain chemical “receptor.” In some cases and with expert medical care, that can be a good thing. But cross that line, and it’s big trouble. Your doctor probably won’t give it to you as an antidepressant yet. Scientists are still testing it for that. But if ketamine does bring people back from the depths of depression, it might be the last thing you expect from a drug that can knock you out.