>I'm not terribly surprised that ketamine may not produce strong antidepressant effects if the patient is not conscious.
That's incorrect, it actually produced larger antidepressant effects (50% response rate and 40% remission [1]) than when the patient is conscious (40% response rate and 30% remission according to a large meta-analysis [2]).
They only measured response for the next three days. Is it possible k has an effect for longer than three days while placebo only lasts three days or so?
Unlikely. I see another comment says "The duration of the antidepressant effect is relatively short (days to weeks) and the antidepressant effect appears to diminish with repeated dosing."
That's incorrect, it actually produced larger antidepressant effects (50% response rate and 40% remission [1]) than when the patient is conscious (40% response rate and 30% remission according to a large meta-analysis [2]).
[1] https://www.medrxiv.org/content/10.1101/2023.04.28.23289210v... [2] https://pubmed.ncbi.nlm.nih.gov/35688035/
But that large response had nothing to do with ketamine, as the non-ketamine group had the same or higher response.