In a unique experiment, ketamine was found to be no better at treating depression than a placebo

New research may complicate our understanding of ketamine as a potential treatment for depression. The study found that people with depression who were given either saline or ketamine before anesthesia for surgery experienced a similar improvement in their symptoms afterwards. The results suggest that at least some of the therapeutic benefits observed with ketamine may be due to the placebo effect, although further research is needed to confirm this.

Many studies have found that low doses of ketamine — long used as both a dissociative sedative and a recreational drug — may also help treat depression and other mental health problems different in some ways of current antidepressants. Some of these studies also involved the use of a placebo control for comparison, which is often considered the best way to determine whether a drug or vaccine actually works as intended (ideally, both the patients and the doctors treating them do not know whether they actually work). (again in the treatment or control group).

The problem is that even low-dose ketamine can cause short-term physical symptoms such as dissociation or a “trip,” making it fairly easy to tell if you are taking it, which then weakens any attempts to develop an appropriate placebo for it Comparison. So researchers at Stanford University decided to conduct a unique experiment to better rule out the possibility of such an event.

Their study involved 40 people with major depressive disorder who were scheduled for routine surgery that required general anesthesia. Half were randomized to receive a single dose of saline, the placebo, and the other half a single dose of intravenous ketamine immediately before surgery. The researchers suspected that the act of submersion would eliminate the likelihood of a typical trip. They then observed the patients for up to three days.

At the end of the study, both groups reported the same average level of improvement in their depression symptoms. Participants correctly guessed whether they had taken ketamine or the placebo less than half of the time or worse than chance, suggesting that the blinding process really worked.

“In conclusion, a single dose of intravenous ketamine during surgical anesthesia had no greater effect than placebo on acutely reducing the severity of depressive symptoms in adults with major depressive disorder,” the authors said wrote in their article published this month in Nature Mental Health.

The study’s results are based on a small sample of patients and a short follow-up period, meaning any interpretations should be viewed with caution until more data is collected. And other researchers have done it already argued that the results may just suggest that surgery and anesthesia in general (which may include ketamine) can offer Rapid relief from depression does not necessarily mean that ketamine does not have a therapeutic effect beyond that of placebo.

The authors say that this hypothesis is unlikely to explain the results because other research has found no consistent association between surgery and improvement in depression (in some people, even). Experience Worsening or new depression after surgery). But they are cautious about the impact of their work. For one thing, they don’t argue that ketamine should be considered just a placebo in the treatment of depression, or that people with depression are somehow faking their illness.

“To say it’s just a placebo is a disservice to placebo,” said study author Boris Heifets, an assistant professor of anesthesiology, in a statement released by Stanford. “It doesn’t mean ‘I’ll feel better if I say it enough times,’ and it doesn’t mean there was nothing wrong with the patient.”

They suggest that people’s positive expectations may be at least part of the reason why ketamine appears to produce such rapid benefits in some people. But even if that were true, that wouldn’t mean that people don’t experience real and positive physical changes when they take it.

“There’s definitely a physiological mechanism, something that happens between the ears when you feel hope,” Heifets said.