> Literally the first Google result for "ketamine opioid" is https://med.stanford.edu/news/all-news/2018/08/ketamines-ant https://med.stanford.edu/news/all-news

> Literally the first Google result for "ketamine opioid" is https://med.stanford.edu/news/all-news/2018/08/ketamines-ant https://med.stanford.edu/news/all-news/2018/08/ketamines-ant.... There is tons of other primary research too. Read the responses to this paper. It has been pretty much debunked. As summarized here: https://onlinelibrary.wiley.com/doi/full/10.1111/pcn.12902 https://onlinelibrary.wiley.com/doi/full/10.1111/pcn.12902 “ However, there has been much debate about this paper.217-221 In contrast, pilot data from Yale University demonstrated that pretreatment with naltrexone did not affect the antidepressant actions of ketamine in patients with depression and alcohol use disorder.222-224 Further clinical trials using a large sample size are needed to better understand whether opioid receptor activation is necessary for ketamine’s antidepressant actions in patients with depression. Recently, we reported that naltrexone did not block the rapid-acting and sustained antidepressant effects of ketamine in a CSDS model or LPS-induced inflammation model.225 If opioid receptors are implicated in the antidepressant actions of ketamine, (S)-ketamine must be more potent than (R)-ketamine in animal models of depression. Therefore, the opioid receptor system might not play a role in ketamine’s antidepressant actions.225”