[rincebrain]

Neuroprotective behavior is one of the theories I've heard about ketamine's efficacy, as well as lithium's, but that doesn't explain the immediate gross improvement, just the eventual semi-permanent tolerance in some cases.

In my case, while it was effective, I was a much more productive and healthy person than I'd ever been, cleaning up lots of mess and accumulated dross I'd never been able to convince myself to go through, more physical activity, more consistent eating...but then it all abruptly came crashing down, eventually, so either the learned behaviors have quite a thresholding behavior, or it's a more complex mechanism.

[cel1ne]

Humans feature meta-cognition. I suspect you felt better and more relaxed due to the mechanism, and that in turn gave you another big boost by showing you that you are still capable to feel and act different.