Effectiveness of meditation retreats: meta-analysis

Khoury, B., at al. (2017). Effectiveness of traditional meditation retreats: A systematic review and meta-analysis. Journal of psychosomatic research92, 16-25, https://doi.org/10.1016/j.jpsychores.2016.11.006. Taken from the Abstract.

Background. An increasing number of studies are investigating traditional retreats. Very little, however, is known about their effectiveness.

Objective. To evaluate the effectiveness of meditation retreats on improving in general population. A total of 20 papers (N = 2912) were included.

Results suggested large effects on measures of anxiety, depression, stress, and moderate effects on measures of emotional regulation and quality of life. As to potential mechanisms of actions, results showed large effects on measures of  mindfulness and compassion, and moderate effects on measures of acceptance. 

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Meditation and prosocial behaviors (review & meta-analysis)

Kreplin, U., Farias, M., & Brazil, I. A. (2018). The limited prosocial* effects of meditation: A systematic review and meta-analysis. Scientific reports, vol. 8, no. 1, pp. 2403, DOI:10.1038/s41598-018-20299-z. Full text.

 Abstract. Many individuals believe that meditation has the capacity to not only alleviate mental-illness but to improve prosociality. This article systematically reviewed and meta-analysed the effects of meditation interventions on prosociality in randomized controlled trials of healthy adults.

Five types of social behaviours were identified: compassion, empathy, aggression, connectedness and prejudice. Although we found a moderate increase in prosociality following meditation, further analysis indicated that this effect was qualified by two factors: type of prosociality and methodological quality.

Meditation interventions had an effect on compassion and empathy, but not on aggression, connectedness or prejudice. We further found that compassion levels only increased under two conditions: when the teacher in the meditation intervention was a co-author in the published study; and when the study employed a passive (waiting list) control group but not an active one.

Contrary to popular beliefs that meditation will lead to prosocial changes, the results of this meta-analysis showed that the effects of meditation on prosociality were qualified by the type of prosociality and methodological quality of the study. We conclude by highlighting a number of biases and theoretical problems that need addressing to improve quality of research in this area.

* Prosocial behavior, or “voluntary behavior intended to benefit another”, is a social behavior that “benefit[s] other people or society as a whole”, “such as helping, sharing, donating, co-operating, and volunteering” (Wikipedia).

Is meditation associated with altered brain structure?

Fox, K. C., et al. (2014). Is meditation associated with altered brain structure? A systematic review and meta-analysis of morphometric neuroimaging in meditation practitioners. Neuroscience & Biobehavioral Reviews, no. 43, pp. 48-73, https://doi.org/10.1016/j.neubiorev.2014.03.016. Full text.

From the Abstract. Numerous studies have begun to address how the brain’s gray and white matter may be shaped by meditation. This research is yet to be integrated, however, and two fundamental questions remain: Is meditation associated with altered brain structure? If so, what is the magnitude of these differences?

To address these questions, we reviewed and meta-analyzed 123 brain morphology differences from 21 neuroimaging studies examining ∼300 meditation practitioners. Anatomical likelihood estimation meta-analysis found eight brain regions consistently altered in meditators, including areas key to meta-awareness (frontopolar cortex/BA 10), exteroceptive and interoceptive body awareness (sensory cortices and insula), memory consolidation and reconsolidation (hippocampus), self and emotion regulation (anterior and mid cingulate; orbitofrontal cortex), and intra- and interhemispheric communication (superior longitudinal fasciculus; corpus callosum). 

Publication bias and methodological limitations are strong concerns, however. Further research using rigorous methods is required to definitively link meditation practice to altered brain morphology.

For an update by the same authors, see “Alterations in the structure of the brain — review & implications.” 

Alterations in the structure of the brain — review & implications

Fox, Kieran C. R., & Rael B. Cahn. (2018). “Meditation and the brain in health and disease.” Forthcoming in The Oxford Handbook of Meditation, Farias, Brazier, & Lalljee, Eds. Full text.

The aim of this chapter is to provide an accessible introduction to the neuroscience of meditation. First, we review studies examining the relationship between meditation and alterations in the structure of the brain’s grey and white matter (so-called morphometric neuroimaging).

Next, we discuss findings from functional neuroimaging methods, such as functional magnetic resonance imaging (fMRI) and positron emission tomography (PET) scans, and what they have taught us about the brain’s patterns of activity during different forms of meditation, how meditation alters the brain’s response to various tasks and experiences, and how the expertise of long-term meditators might be harnessed to help us explore subtle aspects of human cognition.

Third, we review electrophysiological methods of measuring brain activity during meditation, such as electroencephalography (EEG), and how these findings relate to what we have learned from morphometric and functional neuroimaging.

Finally, we discuss the implications of this research and of meditation more generally for brain health and psychological well-being. Specifically, we focus on how meditation might ameliorate the deficits related to cognitive aging, as well as help ameliorate the symptoms and underlying neural substrates associated with neurodegenerative and psychiatric disease.

Towards understanding neuronal mechanisms of meditative states

Irrmischer, M., et al. (2018). Controlling the Temporal Structure of Brain Oscillations by Focused Attention Meditation. Human brain mapping. Vol. 39, no 4, pp. 1825-38, https://doi.org/10.1002/hbm.23971. Full text.

From the Introduction. Meditation is frequently described as a form of mental training to cultivate cognitive capabilities, including attention, concentration, and emotion regulation. With its popularity for attaining relaxation, for physical and mental health, and enhanced awareness and absorption, there is increasing scientific interest in understanding the brain mechanisms involved. . . .

We hypothesized that attention is balanced at a point of instability between order and disorder, characteristic of so‐called critical systems, which allows transient focus and swift change. As practitioners restrain from distraction during meditation to maintain a single focus, we predict that they might experience a shift from more complex brain dynamics to a state of reduced information propagation and reduced temporal complexity of oscillations. Using data from two independent laboratories, we here show that the temporal complexity of neuronal oscillations is affected by FA (focused attention) meditation training. Furthermore, it is sensitive to the meditative state and the subjective experience of absorption.

Mindfulness practices as part of Weight Watchers program

Smith, Deborah. “Exploring the effects of introducing short, manageable mindfulness practises to adults seeking to lose weight in a UK Weight Watchers meeting.”  Proceedings. Dissertation projects, MA in Positive Psychology, Buckinghamshire New University, UK. pp. 43-58.

From the Abstract: Mindfulness and mindful eating are becoming recognised as effective methods in helping people to achieve a healthy weight.  Previous studies have involved relatively lengthy introductions to the practises, sometimes expecting participants to practise the mindfulness meditations for forty-five minutes per day. 

However this study examines participants’ experiences using brief introductions to mindful eating, breathing meditation and loving kindness meditation.  Integrated within a regular weekly Weight Watchers meeting, over a six week period, a fifteen minute introduction was given; a ten minute explanation and five minutes practise.  Two, five or ten minute meditations were suggested for home practise. 

Seven people out of the twenty-five participants were chosen to participate in the focus group used for feedback on the experience.  The interview explored the participants’ experiences of the practises and thematic analysis was used to identify themes within the participants’ accounts.  

The main conclusions from this study are that overweight people seeking to lose weight experience multiple benefits from the brief introductions and mindfulness practises; i.e., reduced stress, increased self-compassion and a more positive relationship with food was developed.  Participants reported an ease of engagement and unanimously wanted to continue practicing mindfulness as part of their on-going weight loss programme and possibly beyond.

Research on spirituality and meditative practices

Kristeller, Jean L., and Kevin D. Jordan. “Spirituality and Meditative Practice: Research Opportunities and Challenges.” Psychological Studies, 20 Mar 2017,  doi:10.1007/s12646-017-0391-0.

Abstract. Meditative practices have a long history in India and have influenced contemporary meditative programs elsewhere in the world. Over the last several decades, the use of meditation as a therapeutic tool has been investigated in regard to physical, emotional and behavioral effects with impressive results. In parallel to this has been a growing interest in research on spirituality, spiritual growth, and therapeutic modalities that incorporate the spiritual dimension of the person.

Ironically, very little research has explored the interface between these two constructs, despite how closely linked they are traditionally. This paper addresses the range of ways in which spirituality and spiritual development might be fruitfully investigated in the context of meditative practice, bringing further understanding to both psychological constructs.

Furthermore, the widely recognized significance of both meditative and spiritual experiences suggests that cross-cultural research may be particularly valuable at identifying factors that engage the universal human capacity of spirituality, and the particular potential for meditative practice in doing so.