In a recent paper that Zindel and I published in the American Psychologist, we argued, “it’s time to get specific about the specific effects of mindfulness-based interventions.” We were not the first to issue this recommendation. It was voiced in a widely-cited review and meta-analysis published in JAMA Internal Medicine in 2014, among others. What exactly does this mean and why should you, as a clinician learning to deliver mindfulness-based interventions, care? All mindfulness-based interventions have multiple components – let’s s take mindfulness-based cognitive therapy (MBCT) as an example. As an MBCT instructor, you teach clients the mindfulness meditation practices, such as the body scan and sitting practices. You also teach mindful stretching and walking meditation, and cognitive behavioral therapy practices, such as monitoring daily experiences, identifying signs of relapse, and creating a relapse prevention action plan. All of this is delivered in the context of a group of participants, who provide a sense of support and community for one another. And, as you develop your expertise in MBCT, you guide meditation, conduct inquiry, and interact with your clients in ways that embody the spirit and intention of mindfulness practice. 

What are the active ingredients of MBCT?

What are the elements that account for the positive effects that MBCT has on your clients’ lives? The truth is that we don’t know the answer to this question, and, in fact, the evidence that is accumulating suggests that the question itself belies some of the complexity.

One of the first studies to explore this question was conducted by Zindel and his colleagues, published in 2010, in which they compared MBCT to antidepressant medication. People with histories of depression who had been successfully treated with medication were randomly assigned to receive MBCT, maintenance medication, or pill placebo. Although people who got MBCT knew that was the intervention, the people who were assigned to a pharmacotherapy group didn’t know if they were getting an active medication or a sugar pill.

Among people who had residual depressive symptoms, MBCT and maintenance medication helped prevent depression to the same extent, and both did significantly better than placebo. This suggests that the relapse prevention effects are specific to something about MBCT and cannot be explained simply by factors that were present also in the placebo condition of the study, such as having a credible rationale, clear steps for what one can do to help prevent depression, expectancies for improvement, and a positive relationship with a professional clinician.

Getting closer to the MBCT secret sauce 

As important as this study was in establishing the efficacy of MBCT, it didn’t really answer the question about the secret sauce within MBCT. To answer this question, we must look to studies that offer interventions that are structurally similar to MBCT but that don’t include certain intervention components--like mindfulness meditation.

Mark Williams and colleagues conducted this very study, which was published in 2014. People with histories of depression were assigned randomly to MBCT, treatment as usual in the community, or a cognitive psychoeducation program that included the didactic elements of relapse prevention in MBCT but no mindfulness practice. Over one year of follow-up, there were no differences in relapse rates among the three groups.

Does this mean that you don’t need the mindfulness to get the benefit of MBCT? Perhaps. However, they also explored differences among people who had histories of childhood trauma, and among this subgroup, there was significant benefit for MBCT. Findings like these, which were not planned before the study was conducted, require replication. They also suggest that asking about the specific ingredients of mindfulness-based interventions might require that we ask about for whom the intervention is being offered.

The first studies of MBCT suggested that its benefits were evident among more vulnerable individuals based on the number of prior episodes that they experienced. It may be the case that group interventions that are structurally equivalent to MBCT offer benefit to people in general, but that the mindfulness meditation component is specifically necessary for people who are more vulnerable, either by virtue of having experienced more episodes of depression or trauma in their past. These are important questions that need to be answered in the coming years.

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