To the Editor A recent publication on the effects of meditation programs against stress1 reviews rigorously randomized clinical trials (RCTs) with active control groups. We would like to point out a couple of unsolved issues that may arise when discussing the impact of these findings.
The review has only collated evidence from RCTs with active control groups. Randomized clinical trials can only be done, by definition, with patients and individuals who are willing to be randomized. Thereby such trials are excluding the potentially most beneficial therapeutic agent: conscious choice and active engagement. Thus, by default, RCTs can only test and describe what is the minimum effect on people who use a certain intervention, as if it were delivered to them as a passive recipient, like a medication. But meditation is no medication. It requires active involvement and the decision to dedicate regularly a specific amount of time, over a larger period in order to change one's habits and attitudes. This can only be assessed in long-term comparative cohort studies that in other conditions and occasions have shown reliable results comparable to RCTs.2
Walach H, Schmidt S, Esch T. Meditation Intervention Reviews. JAMA Intern Med. 2014;174(7):1193-1194. doi:10.1001/jamainternmed.2014.1422