[mikescar]

I've witnessed enough weird ketamine trips to hope nobody close bothers with it again.

It's too sketchy and has a wide variety of effects on people, depending on your brain chemistry. It can produce sedation, or very fast anti-depressant effects, and/or other unusual body responses [1].

[1] http://en.wikipedia.org/wiki/Ketamine#Adverse_effects

[rdl]

Whereas I think it is dramatically underused -- it's a great battlefield or improvised conditions anaesthetic, since it doesn't depress respiration very much. All of the psychiatric features are minor compared to being able to do surgery quickly and not kill the patient.