Mindfulness-Based Stress Reduction reduces pro-inflammatory gene regulation but not systemic inflammation among older adults: A randomized controlled trial.

OBJECTIVE: Aging is associated with increased pro-inflammatory gene expression and systemic inflammation, and psychosocial stress may accelerate these changes. Mindfulness interventions show promise for reducing psychosocial stress and extending healthspan. Inflammatory pathways may play a role. In a sample of lonely older adults, we tested whether mindfulness training reduces proinflammatory gene expression and protein markers of systemic inflammation. METHODS: Lonely older adults (65-85 years; N = 190) were randomly assigned to an 8-week Mindfulness-Based Stress Reduction (MBSR) or matched Health Enhancement Program (HEP). Blood was drawn pre- and post-intervention and at 3-month follow-up. In peripheral blood mononuclear cells (PBMCs), RNA profiling was used to assess transcriptional regulation by pro-inflammatory NF-kB as well as ß-adrenergic CREB, antiviral IRF, and glucocorticoid receptor (GR) transcription factors. Plasma was assayed for proinflammatory markers IL-6 and CRP. Analyses tested time (pre, post, follow-up) by condition (MBSR versus HEP) effects. RESULTS: MBSR reduced NF-kB (d = .17, p = .028) but did not alter CREB (d = .10, p = .20), IRF (d = .13, p = .086), or GR activity (d = .14, p = .063) relative to HEP over time. Contrary to predictions, there were no time × condition effects of MBSR compared to HEP on reducing circulating IL-6 or CRP. CONCLUSIONS: In lonely older adults, MBSR reduced cellular pro-inflammatory gene regulation in ways that would predict reduced disease risk. However, no similar effect was observed for circulating protein markers of inflammation. These results provide specificity about how mindfulness interventions may impact distinct inflammatory markers among aging adults in ways that may have important implications for healthspan. TRIAL REGISTRATION: Clinical Trials identifier NCT02888600.

A systematic review and meta-analysis of the stability of peripheral immune markers in healthy adults.

Peripheral immune markers are widely used to predict risk for inflammatory disease. However, whether single assessments of inflammatory biomarkers represent stable individual differences remains unclear. We reviewed 50 studies (N = 48,674; 57 % male; mean age 54 (range 13-79) years) that assessed markers of inflammation on >1 occasion, with time between measures ranging from 24 h to 7+ years. Separate random effects meta-analyses were conducted for each inflammatory marker and time interval. Markers that had broad coverage across most time intervals included C-reactive protein (CRP; k = 37), interleukin (IL)-6 (k = 22), TNF-α (k = 10), and fibrinogen (Fg; k = 9). For CRP, IL-6, and TNF-α, stability estimates generally decreased with time, with strong to moderate stability over intervals <6 months (r's = 0.80-0.61), modest to moderate stability over 6 months - 3 years (r's = 0.60-0.51), and low stability for >3 years (r's = 0.39-0.30). Estimates were less reliable for Fg for time intervals ≤ 3 years although they generally followed the same pattern; more reliable findings suggested greater stability for Fg than other markers for intervals >3 years (r = 0.53). These findings suggest that single measures of inflammatory biomarkers may be an adequate index of stable individual differences in the short term (<6 months), with repeated measures of inflammatory biomarkers recommended over intervals ≥ 6 months to 3 years, and absolutely necessary over intervals >3 years to reliably identify stable individual differences in health risk. These findings are consistent with stability estimates and clinical recommendations for repeated measurement of other cardiovascular measures of risk (e.g., blood lipids, blood pressure).

Stress-Related Inflammation and Social Withdrawal in Mothers of a Child With Cancer: A 1-Year Follow-Up Study.

OBJECTIVE: Acute inflammation-induced sickness behavior involves changes in social behavior that are believed to promote recovery. Whether chronic inflammation can influence social behaviors in ways that promote recovery is unknown. In a sample of mothers of a child with cancer, this report explores the relationship between inflammation that accompanies the stress of diagnosis and changes in social network, cancer-related stress, and inflammation across 1 year. Three hypotheses tested whether a) initial levels of stress associate with initial levels of inflammation, b) initial levels of inflammation predict social network changes over time, and c) social network changes over time buffer changes in stress and inflammation over time. METHODS: Cancer-related stress (Impact of Events Scale), social network (social roles and contacts from the Social Network Inventory), and systemic inflammation (circulating interleukin [IL]-6) were assessed in 120 mothers three times after their child's cancer diagnosis: after diagnosis (T1), 6-month follow-up (T2), and 12-month follow-up (T3). RESULTS: Consistent with predictions, greater cancer-related stress after diagnosis (T1) was associated with higher IL-6 after diagnosis (T1; b = 0.014, standard error [SE] = 0.01, p = .008). In turn, higher IL-6 after diagnosis (T1) was associated with a decrease in social roles over time (T1 ➔ T3; B = -0.030, SE = 0.01, p = .041). Finally, dropping social roles over time (T1 ➔ T3) was associated with decreases in cancer-related stress (B = 25.44, SE = 12.31, p = .039) and slower increases in IL-6 (B = 1.06, SE = 0.52, p = .040) over time. CONCLUSIONS: This study provides a first indication that chronic stress-related systemic inflammation may predict changes in social behavior that associate with stress recovery and slower increases in inflammation in the year after a major life stressor.

Mindfulness-based stress reduction increases stimulated IL-6 production among lonely older adults: A randomized controlled trial.

Loneliness is a potent psychosocial stressor that predicts poor health and mortality among older adults, possibly in part by accelerating age-related declines in immunocompetence. Mindfulness interventions have shown promise for reducing loneliness and improving markers of physical health. In a sample of lonely older adults, this two-arm parallel trial tested whether mindfulness training enhances stimulated interleukin-6 (IL-6) production, a measure of innate immune responsivity. Lonely older adults (65-85 years; N = 190) were randomized to an 8-week Mindfulness-Based Stress Reduction (MBSR) or control Health Enhancement Program (HEP) intervention. Lipopolysaccharide (LPS)-stimulated production of IL-6 was measured in vitro by blinded outcome assessors at pre-intervention, post-intervention, and 3-month follow-up. Mixed-effects linear models tested time (pre, post, follow-up) by condition (MBSR vs. HEP) effects. As predicted, a significant time × condition effect on stimulated IL-6 production was observed across pre, post, and follow-up timepoints. Significant MBSR vs. HEP differences emerged from pre- to post-intervention (p =.009, d = 0.38) and from pre-intervention to 3-month follow-up (p =.017, d = 0.35), with larger increases in IL-6 production following MBSR compared to HEP. No study-related adverse events were reported. Results show that mindfulness training may be effective for boosting innate immunocompetence among lonely older adults. Given that immunocompetence tends to decline with age, mindfulness training may help to counteract the effects of aging and psychosocial stress on infection risk and recovery from injury.

Mindfulness training reduces loneliness and increases social contact in a randomized controlled trial.

Loneliness and social isolation are a growing public health concern, yet there are few evidence-based interventions for mitigating these social risk factors. Accumulating evidence suggests that mindfulness interventions can improve social-relationship processes. However, the active ingredients of mindfulness training underlying these improvements are unclear. Developing mindfulness-specific skills-namely, (i) monitoring present-moment experiences with (ii) an orientation of acceptance-may change the way people perceive and relate toward others. We predicted that developing openness and acceptance toward present experiences is critical for reducing loneliness and increasing social contact and that removing acceptance-skills training from a mindfulness intervention would eliminate these benefits. In this dismantling trial, 153 community adults were randomly assigned to a 14-lesson smartphone-based intervention: (i) training in both monitoring and acceptance (Monitor+Accept), (ii) training in monitoring only (Monitor Only), or (iii) active control training. For 3 d before and after the intervention, ambulatory assessments were used to measure loneliness and social contact in daily life. Consistent with predictions, Monitor+Accept training reduced daily-life loneliness by 22% (d = 0.44, P = 0.0001) and increased social contact by two more interactions each day (d = 0.47, P = 0.001) and one more person each day (d = 0.39, P = 0.004), compared with both Monitor Only and control trainings. These findings describe a behavioral therapeutic target for improving social-relationship functioning; by fostering equanimity with feelings of loneliness and social disconnect, acceptance-skills training may allow loneliness to dissipate and encourage greater engagement with others in daily life.

Mindfulness-Based Stress Reduction Buffers Glucocorticoid Resistance Among Older Adults: A Randomized Controlled Trial.

OBJECTIVE: Mindfulness interventions have been effective for improving a range of health outcomes; however, pathways underlying these effects remain unclear. Inflammatory processes may play a role, possibly through increased resistance of immune cells to the anti-inflammatory effects of glucocorticoids (i.e., glucocorticoid resistance, or GCR). Here, we conducted an initial examination of whether mindfulness training mitigates GCR among lonely older adults. METHODS: Lonely older adults (65-85 years; n = 190) were randomly assigned to an 8-week Mindfulness-Based Stress Reduction (MBSR) or a matched Health Enhancement Program (HEP). Whole blood drawn before and after the intervention and at 3-month follow-up was incubated with endotoxin and varying concentrations of dexamethasone, and interleukin-6 production was assessed using enzyme-linked immunosorbent assay. GCR was assessed as the concentration of dexamethasone required to decrease the stimulated interleukin-6 response by 50% (half maximal inhibitory concentration), with higher concentrations indicating greater GCR. Mixed-effects linear models tested time (pre, post, follow-up) by condition (MBSR versus HEP) effects. RESULTS: There was no overall time by condition effect on GCR across all time points. However, a significant time by condition effect was observed from preintervention to postintervention (d = 0.29), such that MBSR buffered increases in GCR observed in the HEP group. Although MBSR showed small, nonsignificant reductions in GCR from preintervention to 3-month follow-up, group differences were not maintained at the 3-month follow-up (d = 0.10). CONCLUSIONS: Results suggest that MBSR may protect against declines in the sensitivity of immune cells to the anti-inflammatory effects of glucocorticoids among at-risk lonely older adults and show value in studying this biological mechanism in future trials.Trial Registration: Clinical Trials identifier NCT02888600.

Mindfulness Training and Physical Health: Mechanisms and Outcomes.

OBJECTIVE: There has been substantial research and public interest in mindfulness interventions, biological pathways, and health for the past two decades. This article reviews recent developments in understanding relationships between mindfulness interventions and physical health. METHODS: A selective review was conducted with the goal of synthesizing conceptual and empirical relationships between mindfulness interventions and physical health outcomes. RESULTS: Initial randomized controlled trials in this area suggest that mindfulness interventions can improve pain management outcomes among chronic pain populations, and there is preliminary evidence for mindfulness interventions improving specific stress-related disease outcomes in some patient populations (i.e., clinical colds, psoriasis, irritable bowel syndrome, posttraumatic stress disorder, diabetes, HIV). We offer a stress-buffering framework for the observed beneficial effects of mindfulness interventions and summarize supporting biobehavioral and neuroimaging studies that provide plausible mechanistic pathways linking mindfulness interventions with positive physical health outcomes. CONCLUSIONS: We conclude with new opportunities for research and clinical implementations to consider in the next two decades.

Mindfulness Meditation Training and Executive Control Network Resting State Functional Connectivity: A Randomized Controlled Trial.

OBJECTIVE: Mindfulness meditation training has been previously shown to enhance behavioral measures of executive control (e.g., attention, working memory, cognitive control), but the neural mechanisms underlying these improvements are largely unknown. Here, we test whether mindfulness training interventions foster executive control by strengthening functional connections between dorsolateral prefrontal cortex (dlPFC)-a hub of the executive control network-and frontoparietal regions that coordinate executive function. METHODS: Thirty-five adults with elevated levels of psychological distress participated in a 3-day randomized controlled trial of intensive mindfulness meditation or relaxation training. Participants completed a resting state functional magnetic resonance imaging scan before and after the intervention. We tested whether mindfulness meditation training increased resting state functional connectivity (rsFC) between dlPFC and frontoparietal control network regions. RESULTS: Left dlPFC showed increased connectivity to the right inferior frontal gyrus (T = 3.74), right middle frontal gyrus (MFG) (T = 3.98), right supplementary eye field (T = 4.29), right parietal cortex (T = 4.44), and left middle temporal gyrus (T = 3.97, all p < .05) after mindfulness training relative to the relaxation control. Right dlPFC showed increased connectivity to right MFG (T = 4.97, p < .05). CONCLUSIONS: We report that mindfulness training increases rsFC between dlPFC and dorsal network (superior parietal lobule, supplementary eye field, MFG) and ventral network (right IFG, middle temporal/angular gyrus) regions. These findings extend previous work showing increased functional connectivity among brain regions associated with executive function during active meditation by identifying specific neural circuits in which rsFC is enhanced by a mindfulness intervention in individuals with high levels of psychological distress. CLINICAL TRIAL REGISTRATION: Clinicaltrials.gov,NCT01628809.

Childhood trauma and hair cortisol response over the year following onset of a chronic life event stressor.

OBJECTIVE: Childhood trauma may contribute to poor lifelong health in part through programming of the HPA-axis response to future life stressors. To date, empirical evidence shows an association of childhood trauma with dysregulation of the HPA-axis and blunted cortisol reactivity to acute stressors. Here, we conduct an initial examination of childhood trauma as a moderator of changes over time in perceived stress levels and HPA-axis response to a major chronic stressor in adulthood. METHODS: Participants were 83 maternal caregivers of children newly diagnosed with cancer who completed the Childhood Trauma Questionnaire (CTQ), and who, over the year following their child's cancer diagnosis, had hair samples collected up to 7 times for the assessment of cortisol and completed monthly measures of perceived stress. RESULTS: CTQ scores were in the expected range for a community sample and associated with changes in perceived stress and cortisol concentration over time (γ =.003, p =.002; γ = -.0004, p =.008, respectively) independently of age, education, treatment intensity and randomization to stress management intervention. Maternal caregivers who endorsed lower childhood trauma showed a steeper decline in perceived stress and a larger increase in cortisol levels across the year than caregivers who recalled more childhood trauma. CONCLUSIONS: Findings extend animal models and studies that examine cortisol reactivity to acute stressors and suggest that childhood trauma may program a phenotype that is more psychologically reactive but shows a blunted HPA-axis response to chronic stress. While adaptive in the short-term, this early life programming may incur long-term costs for health. Further work is warranted to examine this possibility.

Mindfulness interventions for offsetting health risk following early life stress: Promising directions.

Early life stress (ELS), common to childhood maltreatment, socioeconomic disadvantage, and racial discrimination, is thought to create a proinflammatory phenotype that increases risk for poor health in adulthood. Systemic change is needed to address the root causes of ELS, but a substantial number of adults are already at increased health risk by virtue of ELS exposure. Interventions that target stress pathways have the potential to interrupt the trajectory from ELS to inflammatory disease risk in adulthood. Mindfulness-based interventions (MBIs), which train acceptance toward present-moment experience, have shown promise for reducing stress and improving a variety of stress-sensitive health outcomes. Although MBIs have primarily been conducted in more advantaged populations, evidence suggests that they may be uniquely effective for improving mental health and health-related quality of life among those with a history of ELS. Whether these effects extend to physical health remains unknown. To shed light on this question, I review evidence that MBIs influence inflammatory markers in at-risk samples, explore the promise of MBIs for improving stress-related health outcomes in diverse at-risk populations, and describe adaptations to MBIs that may increase their acceptability and efficacy in populations exposed to ELS. This prior work sets the stage for well-controlled RCTs to evaluate whether MBIs influence stress and inflammatory pathways among those exposed to ELS and for pragmatic and implementation trials focused on disseminating MBIs to reach these at-risk populations. Overall, the evidence assembled here shows the potential of MBIs for offsetting physical health risk related to ELS.

Punishment on Pause: Preliminary Evidence That Mindfulness Training Modifies Neural Responses in a Reactive Aggression Task.

Reactive aggression, a hostile retaliatory response to perceived threat, has been attributed to failures in emotion regulation. Interventions for reactive aggression have largely focused on cognitive control training, which target top-down emotion regulation mechanisms to inhibit aggressive impulses. Recent theory suggests that mindfulness training (MT) improves emotion regulation via both top-down and bottom-up neural mechanisms and has thus been proposed as an alternative treatment for aggression. Using this framework, the current pilot study examined how MT impacts functional brain physiology in the regulation of reactive aggression. Participants were randomly assigned to 2 weeks of MT (n = 11) or structurally equivalent active coping training (CT) that emphasizes cognitive control (n = 12). Following training, participants underwent functional magnetic resonance imaging (fMRI) during a retaliatory aggression task, a 16-trial game in which participants could respond to provocation by choosing whether or not to retaliate in the next round. Training groups did not differ in levels of aggression displayed. However, participants assigned to MT exhibited enhanced ventromedial prefrontal cortex (vmPFC) recruitment during punishment events (i.e., the aversive consequence of losing) relative to those receiving active CT. Conversely, the active coping group demonstrated greater dorsomedial prefrontal cortex (dmPFC) activation when deciding how much to retaliate, in line with a bolstered top-down behavior monitoring function. The findings suggest that mindfulness and cognitive control training may regulate aggression via different neural circuits and at different temporal stages of the provocation-aggression cycle. Trial Registration: identification no. NCT03485807.

Mindfulness interventions improve momentary and trait measures of attentional control: Evidence from a randomized controlled trial.

Mindfulness interventions have been shown to improve several subcomponents of attention; however, the psychological mechanisms driving these improvements are unknown. Mindfulness interventions train individuals to monitor present moment experiences while adopting an attitude of acceptance toward these experiences. We conducted a theoretically driven randomized controlled trial to test the putative mechanisms of mindfulness training that drive improvements in attentional control. Participants were randomly assigned to 1 of 3 conditions: (a) monitor and accept (MA) training, a standard 8-week mindfulness-based stress reduction (MBSR) intervention that included cultivation of both monitoring and acceptance skills; (b) monitor only (MO) training, a well-matched modified 8-week MBSR-adapted intervention that focused on monitoring skills only; or (c) no treatment (NT) control. Momentary attentional control was measured via ecological momentary assessment for 3 days at baseline and postintervention. Trait attentional control was assessed at baseline and postintervention using traditional self-report. Participants also completed a dichotic listening task to assess sustained attention at baseline and postintervention. We found that MA and MO participants improved in momentary and trait attentional control (but not attention task performance) relative to NT participants. Analyses of indirect effects were consistent with the possibility that increased momentary attentional control partially accounts for MA/MO intervention-related increases in trait attentional control. This randomized controlled trial provides one of the first experimental tests of the mechanisms of mindfulness interventions that drive improvements in attention outcomes. These findings support the notion that present-focused monitoring skills training drives mindfulness intervention-related improvements in momentary attentional control, which in turn fosters greater trait attentional control. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Mindfulness, acceptance, and emotion regulation: perspectives from Monitor and Acceptance Theory (MAT).

Experiential acceptance-an orientation of receptivity and noninterference with present-moment experiences-is described as central to mindfulness interventions, yet little experimental work has tested acceptance as a mechanism for mindfulness intervention effects. Guided by Monitor and Acceptance Theory (MAT), this review situates acceptance as an emotion regulation mechanism and reviews self-report mindfulness literature showing that attention monitoring skills are only associated with beneficial mental and physical health outcomes when accompanied by acceptance skills. New experimental dismantling work shows that removing acceptance training from mindfulness interventions reduces their efficacy for improving stress, positive emotion, and social relationship outcomes. Overall, converging evidence demonstrates that acceptance is a critical emotion regulation mechanism of mindfulness interventions. This work advances basic research, has translational value, and offers opportunities for future research.

Mindfulness training and systemic low-grade inflammation in stressed community adults: Evidence from two randomized controlled trials.

Mindfulness interventions have garnered significant attention as a complementary health treatment for many physical and psychological conditions. While some research has shown that mindfulness training can decrease psychological and physiological stress responses, it remains unclear whether mindfulness training impacts inflammation-a predictor of poor health outcomes. In addition, little research has examined the active components of mindfulness that may drive health-related improvements. Here, we provide data from two 3-arm randomized controlled trials that examined the effect of mindfulness training on inflammation in stressed community adults. Specifically, we examined whether training individuals to have an accepting attitude towards present moment experiences is a key emotion regulation skill that can lead to decreases in inflammation. Both studies randomly assigned participants to one of three conditions: mindfulness training that taught both attention monitoring and acceptance skills (Monitor+Accept); mindfulness training teaching monitoring without the acceptance component (Monitor Only); or a control condition. Study 1 employed a novel 2-week smartphone-based intervention and Study 2 employed a standard 8-week Mindfulness-Based Stress Reduction (MBSR) intervention. We hypothesized that Monitor+Accept training would lead to reductions in the inflammatory biomarker C-Reactive Protein (CRP) compared to Monitor Only training and control groups. Contrary to this hypothesis, we found that Monitor+Accept mindfulness training did not lead to reductions in CRP. Exploratory analyses combining study subsamples, however, suggest that both mindfulness interventions may reduce CRP in populations at risk for systemic inflammation-midlife-to-older adults and individuals with high BMI. Overall, the present studies contribute significantly to the question of whether mindfulness interventions can reduce systemic markers of low-grade inflammation.

Psychological mechanisms driving stress resilience in mindfulness training: A randomized controlled trial.

OBJECTIVE: Mindfulness interventions have been shown to reduce stress; however, the mechanisms driving stress resilience effects are not known. Mindfulness interventions aim to teach individuals how to: (a) use attention to monitor present moment experiences; with (b) an attitude of acceptance and equanimity. A randomized controlled dismantling trial (RCT) was conducted to test the prediction that the removal of acceptance skills training would eliminate stress-reduction benefits of a mindfulness intervention. METHOD: This preregistered RCT randomly assigned stressed community adults to 1 of 3 conditions: (a) Monitor and Accept (MA) mindfulness training, a standard 8-week Mindfulness-Based Stress Reduction (MBSR) intervention that provided explicit instruction in developing both monitoring and acceptance skills; (b) Monitor Only (MO) mindfulness training, a well-matched 8-week MBSR intervention that taught monitoring skills only; or (c) No Treatment (NT) control. Stress and nonjudgment were measured using ecological momentary assessment (EMA) for 3 days at baseline and 3 days at postintervention. RESULTS: Consistent with predictions, MA participants increased in nonjudgment and decreased in both stress ratings and the proportion of assessments that they reported experiencing feelings of stress in daily life, relative to both MO and NT participants. CONCLUSIONS: This RCT provides one of the first experimental tests of the mechanisms linking mindfulness interventions with stress resilience. These findings suggest that acceptance skills training may be a necessary active ingredient and support the value of integrating acceptance skills training into stress-reduction interventions. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Brief mindfulness training for negative affectivity: A systematic review and meta-analysis.

OBJECTIVE: Over the last 10 years, there has been a dramatic increase in published randomized controlled trials (RCTs) of brief mindfulness training (from single-session inductions to multisession interventions lasting up to 2 weeks), with some preliminary indications that these training programs may improve mental health outcomes, such as negative affectivity. This meta-analysis aimed to evaluate whether brief mindfulness training reliably reduces negative affectivity. METHOD: PubMed, PsycINFO, and the Mindfulness Research Monthly Newsletter were systematically searched for brief mindfulness intervention RCTs assessing negative affectivity outcomes (e.g., depression, rumination, anxiety, stress). Sixty-five RCTs, including 5,489 participants predominantly without experience in meditation (64.64% female, mean age = 24.62), qualified for the meta-analytic review. RESULTS: The meta-analysis revealed a small but significant effect of brief mindfulness training on reducing negative affectivity compared to control programs (g = .21, p < .001). The overall effect size was significantly moderated by participant characteristics: community samples (g = .41, p < .001) produced larger training effects compared to student samples (g = .14, p = .001; Qbetween p = .03). No significant effect size differences were found between clinical and nonclinical samples. However, when accounting for publication bias, the overall effect size of brief mindfulness training programs on negative affectivity was significantly reduced (g = .04). CONCLUSIONS: Brief mindfulness training programs are increasingly popular approaches for reducing negative affectivity. This meta-analysis indicates that brief mindfulness training modestly reduces negative affectivity. Quantitative analyses indicated the presence of publication bias (i.e., unpublished null effect studies), highlighting the need to continue rigorous evaluation of brief mindfulness interventions. (PsycINFO Database Record

Acceptance lowers stress reactivity: Dismantling mindfulness training in a randomized controlled trial.

OBJECTIVE: Mindfulness interventions, which train practitioners to monitor their present-moment experience with a lens of acceptance, are known to buffer stress reactivity. Little is known about the active mechanisms driving these effects. We theorize that acceptance is a critical emotion regulation mechanism underlying mindfulness stress reduction effects. METHOD: In this three-arm parallel trial, mindfulness components were dismantled into three structurally equivalent 15-lesson smartphone-based interventions: (1) training in both monitoring and acceptance (Monitor+Accept), (2) training in monitoring only (Monitor Only), or (3) active control training (Coping control). 153 stressed adults (mean age=32years; 67% female; 53% white, 21.5% black, 21.5% Asian, 4% other race) were randomly assigned to complete one of three interventions. After the intervention, cortisol, blood pressure, and subjective stress reactivity were assessed using a modified Trier Social Stress Test. RESULTS: As predicted, Monitor+Accept training reduced cortisol and systolic blood pressure reactivity compared to Monitor Only and control trainings. Participants in all three conditions reported moderate levels of subjective stress. CONCLUSIONS: This study provides the first experimental evidence that brief smartphone mindfulness training can impact stress biology, and that acceptance training drives these effects. We discuss implications for basic and applied research in contemplative science, emotion regulation, stress and coping, health, and clinical interventions.

How mindfulness training promotes positive emotions: Dismantling acceptance skills training in two randomized controlled trials.

Mindfulness meditation interventions-which train skills in monitoring present-moment experiences with a lens of acceptance-have shown promise for increasing positive emotions. Using a theory-based approach, we hypothesized that learning acceptance skills in mindfulness interventions helps people notice more positive experiences in daily life, and tested whether removing acceptance training from mindfulness interventions would eliminate intervention-related boosts in positive affect. In 2 randomized controlled trials (RCTs) of stressed community adults, mindfulness skills were dismantled into 2 structurally equivalent interventions: (a) training in both monitoring and acceptance (Monitor + Accept) and (b) training in monitoring only (Monitor Only) without acceptance training. Study 1 tested 8-week group-based Monitor + Accept and Monitor Only interventions compared with a no treatment control group. Study 2 tested 2-week smartphone-based Monitor + Accept and Monitor Only interventions compared with an active control training. In both studies, end-of-day and momentary positive affect and negative affect were measured in daily life for 3 days pre- and post-intervention using ambulatory assessments. As predicted, across 2 RCTs, Monitor + Accept training increased positive affect compared with both Monitor Only and control groups. In Study 1, this effect was observed in end-of-day positive affect. In Study 2, this effect was found in both end-of-day and momentary positive affect outcomes. In contrast, all active interventions in Studies 1 and 2 decreased negative affect. These studies provide the first experimental evidence that developing an orientation of acceptance toward present-moment experiences is a central mechanism of mindfulness interventions for boosting positive emotions in daily life. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

Mechanisms of mindfulness training: Monitor and Acceptance Theory (MAT).

Despite evidence linking trait mindfulness and mindfulness training with a broad range of effects, still little is known about its underlying active mechanisms. Mindfulness is commonly defined as (1) the ongoing monitoring of present-moment experience (2) with an orientation of acceptance. Building on conceptual, clinical, and empirical work, we describe a testable theoretical account to help explain mindfulness effects on cognition, affect, stress, and health outcomes. Specifically, Monitor and Acceptance Theory (MAT) posits that (1), by enhancing awareness of one's experiences, the skill of attention monitoring explains how mindfulness improves cognitive functioning outcomes, yet this same skill can increase affective reactivity. Second (2), by modifying one's relation to monitored experience, acceptance is necessary for reducing affective reactivity, such that attention monitoring and acceptance skills together explain how mindfulness improves negative affectivity, stress, and stress-related health outcomes. We discuss how MAT contributes to mindfulness science, suggest plausible alternatives to the account, and offer specific predictions for future research.