Are randomized controlled trials the “gold standard” of evidence for mindfulness-based interventions?

Abstract Mindfulness-based interventions (MBIs) are behavioral programs, often involving practices like meditation, that aim to cultivate mindfulness , the nonjudgmental awareness of present-moment experience. A growing body of evidence suggests that they are effective for treating a range of physical and mental health conditions. Critics, however, argue that much of this evidence is biased, relying heavily on uncontrolled or poorly controlled studies, and is therefore insufficient to warrant the widespread clinical adoption of MBIs. More randomized controlled trials (RCTs)—widely regarded as the “gold standard” of scientific evidence—are needed (Van Dam et al., 2018). In this paper, I argue that, although RCT study design has several advantages, it also embodies reductionistic assumptions about how and why an intervention produces its effects. In particular, it assumes that such effects can be attributed to a single, isolable “active ingredient.” In contrast, the features of MBIs, including the attitudes and forms of effort they require, are not readily decomposable into “ingredients.” Moreover, a prominent attempt to isolate mindfulness as an active ingredient (MacCoon et al., 2012) ultimately does not succeed. I conclude that RCTs should not be treated as the gold standard of evidence for MBIs or other complex behavioral interventions for which these assumptions may not hold. Doing so undermines the value of evidence for nonreductionistic hypotheses about how they function and risks underestimating their effectiveness.