Jon Kabat-Zinn created the eight-week Mindfulness-Based Stress Reduction (MBSR) program in the late 1970s. Although eight weeks of MBSR do not appear to alter brain structure, contrary to some earlier studies, MBSR is still regarded as a useful method for lowering stress, managing generalized anxiety disorder, controlling pain, and improving overall emotion regulation.
The most recent study (Kral et al., 2022) into whether eight weeks of MBSR causes structural brain changes in gray matter or cortical thickness combined datasets from two significant, three-arm randomized controlled trials involving hundreds of participants (n=218) who had baseline and post-intervention MRI brain scans.
The Center for Healthy Minds at the University of Wisconsin-Madison, led by first author Tammi Kral, senior author Richard Davidson, and collaborators, published these findings on May 20 in the peer-reviewed journal Science Advances.
“Previous findings from a few small studies have permeated popular media with the notion that a few weeks of training in MBSR can lead to measurable changes in brain structure and have been cited over 3,200 times combined,” the authors note in their paper’s introduction.
See here, here, and here for further information on how mindfulness came to be overhyped while its potential drawbacks are frequently disregarded.
In the largest and most rigorously controlled study to date, we failed to replicate prior findings and found no evidence that MBSR produced neuroplastic changes compared to either control group, at either the whole-brain level or in regions of interest drawn from prior MBSR studies.
Kral et al.
Short-Term MBSR Does Not Change Brain Structure
The results of Davidson’s team’s evaluation of gray matter volume (GMV), gray matter density (GMD), and cortical thickness (CT) at baseline and eight weeks did not support prior studies that claimed that short-term mindfulness training alters brain structure.
“In the largest and most rigorously controlled study to date, we failed to replicate prior findings and found no evidence that MBSR produced neuroplastic changes compared to either control group, at either the whole-brain level or in regions of interest drawn from prior MBSR studies,” Kral et al. explain.
These results lead the researchers to hypothesize that for mindfulness or meditation practice to alter brain structure, “interventions lasting longer than the typical 8-week MBSR course” or “singularly focused on one specific meditation practice” may be necessary.
Previous MBSR-Related Brain Structure Studies Had Limitations
Previous research on MBSR-related changes in brain structure following eight weeks of mindfulness training, according to the authors, had substantial flaws such limited sample numbers, a lack of active control groups or randomization, and a reliance on circular analysis.
Notably, Davidson and his team predicted that the duration of MBSR practice would be related to structural brain alterations in GMV, GMD, and CT before they began their most recent randomized controlled studies. They were unable to duplicate and build upon prior studies, but they nonetheless published their findings.
This is significant because contradictory study results are frequently hidden in a filing cabinet or brushed under the rug. As a result, they are never published.
The so-called “File Drawer Problem,” which is a symptom of the replication crisis, has the potential to spread false information because the scientific community and the general public rarely learn about research that produce null results or fail to repeat prior findings.
“As more research is conducted on mindfulness meditation, the importance of reporting results of conceptual and direct replication attempts should be emphasized considering known publication bias for positive findings,” Kral et al. write.
Future studies should examine “individual differences in engagement and efficacy of MBSR,” according to the most recent paper by Richard Davidson and colleagues at the Center for Healthy Minds, and they should also look into the ideal “dose” (duration/frequency) of mindfulness training or meditation practice.
“We are still in the early stages of research on the effects of meditation training on the brain, and there is much to be discovered,” Davidson said in a May 2022 news release.
