[yesseri]

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.

[OldfieldFund]

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.

[milchek]

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.

[AndrewThrowaway]

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?

[cassianoleal]

> 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.

[nemomarx]

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

[sorcerer-mar]

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

[mock-possum]

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

[sorcerer-mar]

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.