I'm wondering, isn't it the same as placebo effect? In that it's not a change that occurs from taking a medication. It's a change that is the result of mental state change. Both can produce a physical change, as studies have shown (no link, sorry). But one is entirely the result of mental processes, though those mental processes were not induced by a placebo pill. So it's basically the same as the placebo effect, isn't it?

What would you consider a placebo for meditation?

a "placebo" generally refers to an inactive control arm of a study of a drug. For studying something like meditation, you would use a different kind of control arm. The most common example is "treatment as usual". So half of ppl get meditation therapy for a given condition (say, depression), half get "treatment as usual" (pills and Or therapy). This has lots of problems as "treatment as usual" varies a lot from patient to patient, doctor to doctor

A better control is basically taking every aspect of mindfulness based therapy except for the mindfulness (i.e. You educate the patient about the condition, have a group therapy session with a healthcare provider, have at-home therapy assignments, etc). You standardize this "active control" and compare how patients do with this intervention compared to the mindfulness based intervention. This isolates the effect of mindfulness vs other potential confounding effects, and also should reduce physician to physician variability

In the one large study of mindfulness interventions using this active control, there was no measurable benefit to the mindfulness arm

I want to reply here as well:

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3964149/

The study you mentioned shows that mindfulness is overall as effective as the (best?) known other treatment options. If you take this literally you are right, there is no "benefit" in choosing mindfulness based therapy over the other options. It is "only" on par with the other known treatment options.

It is therefore a fully valid and effective choice for treatment.

i guess an analogy that could be appropriate here is to imagine there is a study that compares two interventions for treating cancer: chemotherapy as one intervention, and chemotherapy plus playing video games for several hours as another intervention. Let's say that both interventions provide the same benefit in terms of killing the tumor, helping patients live longer. Does this suggest that playing video games for several hours is an effective treatment for cancer?

The control in that study was specifically designed to "unpack" mbct into its components, and then test mindfulness + other components vs just the other components. When they did that, both arms looked equal

I meditate regularly and don't doubt it helps me, and I think if people actually committed to studying mindfulness rigorously they'd find great things, but it's a shame that most mindfulness research isn't that robust or rigorous