Is it possible to have a placebo group when doing a study on psilocybin? Would participants in the placebo not notice the lack of psychedelic effects?

EDIT: In the original link it says the placebo group received a much lower dose, so that seems to be one way of doing it.

Then again what if showing some funky hallucinogenic images/movies would have the same effect on some people? We surely know that people can go crazy (so have psychological effects) in cults and similar settings. What if intense visual/sonic/etc stimulation, visual distortions etc. together with messaging like "it will change your life and cure your anxieties" is the key in this therapy?

> intense visual/sonic/etc stimulation, visual distortions etc. together with messaging like "it will change your life and cure your anxieties" is the key in this therapy?

I sincerely hope this is not at all how any of this works. That sounds like a recipe for paranoia.

That's not so much a placebo as a head to head test of different effects? I think you'd do it in a new study entirely

That isn't how these studies are being done... because yeah, it'd probably confound the results.

One way is using niacin in high doses, also known as vitamin B3, as an active placebo to induce a sensation of heat and cause the skin to flush red, which is a typical reaction to tryptamines.

The rest is a regular placebo. It can be a really strong thing when you are feeling hot.

sounds like in that case you’re not testing the efficacy of high versus sober, you’re testing heroic dosing versus micro dosing.

There are also studies that test against placebo. There have been lots and lots of trials on these things with different designs that make different cost/benefit tradeoffs.

A difficult one with psychedelics is as-mentioned: people can easily "break the blind". But if you want to eliminate that problem you can instead do a micro vs macro dose, in which case you're measuring a slightly different thing.

I suppose different trials do it in various ways, for hers there was a placebo group that was given a strong antihistamine. Participants in the trial were allowed to opt in for the real dosing day once the trial concluded. I suppose this was to entice people to join, as otherwise it was basically 50/50 if you would get the trial treatment you were looking for. Post trial dosing was obviously omitted from the results.

There was a placebo group that were given basically a very strong antihistamine which induced some drowsiness.

This particular trial, however, allowed participants who were in the placebo group to later opt in for the real dosing - obviously with those results omitted from the trial.