Mental and Physical Health Impacts of Mindfulness Training for College Undergraduates: A Systematic Review and Meta-Analysis of Randomized Controlled Trials.

Background: Universities increasingly offer mindfulness-based programs (MBPs) to improve student health and reduce their impact on overburdened psychological services. It is critical for evidence-based policy to determine for what health outcomes mindfulness programs are effective and under what conditions. Objectives were to: (a) perform a comprehensive analysis of the effects of mindfulness interventions on physical, mental, and behavioral health outcomes in college undergraduate students, and (b) examine moderators of intervention effects to identify factors that may help improve existing university mindfulness programs and guide the design of new programs. Method: Systematic searches of five databases identified MBP randomized controlled trials for undergraduate students, measuring any health outcome. Analyses using robust variance estimation focused on standardized mean differences for outcomes between groups and modeled through coded study features. Results: The 58 studies in the review primarily focused on mental health with fewer assessments of physical health or health behaviors. Overall, mindfulness interventions significantly outperformed both active and inactive controls (ps<.05), with the most marked effects on anxiety symptoms, depressive symptoms, and mindfulness; greater success appeared for clinical populations. Online programs performed equivalent to in-person, and non-MBP programs were equivalent to MBP programs after controlling for other factors. Publication bias and other quality issues also emerged. Conclusions: Mindfulness programs improve well-being in college students, with the strongest evidence for reducing anxiety and depressive symptoms. More studies utilizing stronger methods are needed to evaluate mindfulness programs' effects on additional health outcomes and online interventions in clinical populations.

The Effect of Mindfulness-based Programs on Cognitive Function in Adults: A Systematic Review and Meta-analysis.

Mindfulness-based programs (MBPs) are increasingly utilized to improve mental health. Interest in the putative effects of MBPs on cognitive function is also growing. This is the first meta-analysis of objective cognitive outcomes across multiple domains from randomized MBP studies of adults. Seven databases were systematically searched to January 2020. Fifty-six unique studies (n = 2,931) were included, of which 45 (n = 2,238) were synthesized using robust variance estimation meta-analysis. Meta-regression and subgroup analyses evaluated moderators. Pooling data across cognitive domains, the summary effect size for all studies favored MBPs over comparators and was small in magnitude (g = 0.15; [0.05, 0.24]). Across subgroup analyses of individual cognitive domains/subdomains, MBPs outperformed comparators for executive function (g = 0.15; [0.02, 0.27]) and working memory outcomes (g = 0.23; [0.11, 0.36]) only. Subgroup analyses identified significant effects for studies of non-clinical samples, as well as for adults aged over 60. Across all studies, MBPs outperformed inactive, but not active comparators. Limitations include the primarily unclear within-study risk of bias (only a minority of studies were considered low risk), and that statistical constraints rendered some p-values unreliable. Together, results partially corroborate the hypothesized link between mindfulness practices and cognitive performance. This review was registered with PROSPERO [CRD42018100904].

From Self-Esteem to Selflessness: An Evidence (Gap) Map of Self-Related Processes as Mechanisms of Mindfulness-Based Interventions.

Self-related processes (SRPs) have been theorized as key mechanisms of mindfulness-based interventions (MBIs), but the evidence supporting these theories is currently unclear. This evidence map introduces a comprehensive framework for different types of SRPs, and how they are theorized to function as mechanisms of MBIs (target identification). The evidence map then assesses SRP target engagement by mindfulness training and the relationship between target engagement and outcomes (target validation). Discussion of the measurement of SRPs is also included. The most common SRPs measured and engaged by standard MBIs represented valenced evaluations of self-concept, including rumination, self-compassion, self-efficacy, and self-esteem. Rumination showed the strongest evidence as a mechanism for depression, with other physical and mental health outcomes also supported. Self-compassion showed consistent target engagement but was inconsistently related to improved outcomes. Decentering and interoception are emerging potential mechanisms, but their construct validity and different subcomponents are still in development. While some embodied self-specifying processes are being measured in cross-sectional and meditation induction studies, very few have been assessed in MBIs. The SRPs with the strongest mechanistic support represent positive and negative evaluations of self-concept. In sum, few SRPs have been measured in MBIs, and additional research using well-validated measures is needed to clarify their role as mechanisms.

Emotion-related constructs engaged by mindfulness-based interventions: A systematic review and meta-analysis.

OBJECTIVES: Mindfulness-based interventions (MBIs) have been widely implemented to improve self-regulation behaviors, often by targeting emotion-related constructs to facilitate change. Yet the degree to which MBIs engage specific measures of emotion-related constructs has not been systematically examined. METHODS: Using advanced meta-analytic techniques, this review examines construct and measurement engagement in trials of adults that used standardized applications of the two most established MBIs: Mindfulness-Based Stress Reduction (MBSR) and Mindfulness-Based Cognitive Therapy (MBCT), or modified variations of these interventions that met defined criteria. RESULTS: Seventy-two studies (N=7,378) were included (MBSR k=47, MBCT k = 21, Modified k=4). MBIs led to significant improvement in emotion-related processing overall, compared to inactive controls (d=0.58; k =36), and in all constructs assessed: depression (d=0.66; k=26), anxiety (d =0.63; k=19), combined mental health (d =0.75; k=7 ) and stress (d =0.44; k=11). Reactions to pain, mood states, emotion regulation, and biological measures lacked sufficient data for analysis. MBIs did not outperform active controls in any analyses. Measurement tool and population-type did not moderate results, but MBI-type did, in that MBCT showed stronger effects than MBSR, although these effects were driven by a small number of studies. CONCLUSIONS: This review is the first to examine the full scope of emotion-related measures relevant to self-regulation, to determine which measures are most influenced by MBCT/MBSR. Compared to extant reviews, which typically focused on MBI outcomes, this work examined mechanistic processes based on measurement domains and tools. While effect sizes were similar among measurement tools, this review also includes a descriptive evaluation of measures and points of caution, providing guidance to MBI researchers and clinicians for selection of emotion-related measurement tools.

Therapeutic Effects of Meditation, Yoga, and Mindfulness-Based Interventions for Chronic Symptoms of Mild Traumatic Brain Injury: A Systematic Review and Meta-Analysis.

BACKGROUND: Chronic symptoms of mild traumatic brain injury (mTBI) vary greatly and are difficult to treat; we investigate the impact of meditation, yoga, and mindfulness-based interventions on this treatment group. METHOD: Search included four databases, allowing studies of any design containing pre/post outcomes for meditation, yoga, or mindfulness-based interventions in people suffering from brain injury acquired by mechanical force. Analyses used robust variance estimation to assess overall effects and random-effects models for selected outcomes; we evaluated both between- and within-group changes. RESULTS: Twenty studies (N = 539) were included. Results revealed significant improvement of overall symptoms compared to controls (d = 0.41; 95% CI [0.04, 0.77]; τ2  = 0.06), with significant within-group improvements in mental health (d = 0.39), physical health (d = 0.39), cognitive performance (d = 0.24), quality of life (d = 0.39), and self-related processing (d = 0.38). Symptoms showing greatest improvement were fatigue (d = 0.96) and depression (d = 0.40). Findings were homogeneous across studies. Study quality concerns include lack of randomisation, blinding, and recording of adverse events. CONCLUSIONS: This first-ever meta-analysis on meditation, yoga, and mindfulness-based interventions for chronic symptoms of mTBI offers hope but highlights the need for rigorous new trials to advance clinical applications and to explore mechanistic pathways.

Yoga as Antihypertensive Lifestyle Therapy: A Systematic Review and Meta-analysis.

OBJECTIVE: To investigate the efficacy of yoga as antihypertensive lifestyle therapy and identify moderators that account for variability in the blood pressure (BP) response to yoga. METHODS: We systematically searched 6 electronic databases from inception through June 4, 2018, for articles published in English language journals on trials of yoga interventions that involved adult participants, reported preintervention and postintervention BP, and had a nonexercise/nondiet control group. Our search yielded 49 qualifying controlled trials (56 interventions). We (1) evaluated the risk of bias and methodological study quality, (2) performed meta-regression analysis following random-effects assumptions, and (3) generated additive models that represented the largest possible clinically relevant BP reductions. RESULTS: On average, the 3517 trial participants were middle-aged (49.2±19.5 years), overweight (27.9±3.6 kg/m2) adults with high BP (systolic BP, 129.3±13.3 mm Hg; diastolic BP, 80.7±8.4 mm Hg). Yoga was practiced 4.8±3.4 sessions per week for 59.2±25.0 minutes per session for 13.2±7.5 weeks. On average, yoga elicited moderate reductions in systolic BP (weighted mean effect size, -0.47; 95% CI, -0.62-0.32, -5.0 mm Hg) and diastolic BP (weighted mean effect size, -0.47; 95% CI, -0.61 to -0.32; -3.9 mm Hg) compared with controls (P<.001 for both systolic BP and diastolic BP). Controlling for publication bias and methodological study quality, when yoga was practiced 3 sessions per week among samples with hypertension, yoga interventions that included breathing techniques and meditation/mental relaxation elicited BP reductions of 11/6 mm Hg compared with those that did not (ie, 6/3 mm Hg). CONCLUSION: Our results indicate that yoga is a viable antihypertensive lifestyle therapy that produces the greatest BP benefits when breathing techniques and meditation/mental relaxation are included.