First, do no harm: An intensive experience sampling study of adverse effects to mindfulness training.

OBJECTIVE: The study of safety and adverse effects of mindfulness-based interventions (MBIs) is limited. We propose a novel reliable change index (RCI) approach to experience sampling (ES) data to begin to understand the common domains, frequency, severity, risk for, and context of adverse responding to mindfulness meditation practice and brief MBI. METHODS: Over the course of a 21-day MBI among 82 meditation-naïve participants, we estimated (i) momentary adverse effects during mindfulness meditation practice and (ii) sustained adverse effects in daily living following the intervention. RESULTS: First, RCI analyses of experience sampling of mindfulness meditation document that 87% of participants demonstrated at least one momentary adverse effect during meditation, most commonly anxiety; and subject-level temporal variability or instability in experience samples of daily living did not account for momentary adverse effects attributed to mindfulness meditation sessions. Second, 25% of participants experienced a sustained adverse effect in daily living at post-intervention. Yet, neither momentary adverse effects to meditation nor vulnerability factors at pre-intervention predicted adverse effects at post-intervention. CONCLUSIONS: Findings illustrate that mindfulness meditation may be transiently anxiogenic for many participants, yet, these experiences are unlikely to constitute objective harm per se. Furthermore, observed deterioration in daily living post-intervention cannot be attributed to momentary adverse effects in response to mindfulness meditation. We speculate that observed deterioration in daily living post-intervention may thus be better explained by increased awareness to internal states following mindfulness training. Findings highlight the potential utility of applying a RCI approach to intensive ES measurement to quantify adverse effects of mindfulness training specifically and mental health interventions broadly.

The Daily Dose-Response Hypothesis of Mindfulness Meditation Practice: An Experience Sampling Study.

OBJECTIVE: Because of fast-growing interest in the applications of mindfulness to promote well-being and mental health, there are field-wide efforts to better understand how mindfulness training works and thereby to optimize its delivery. Key to these efforts is the role of home practice in mindfulness-based intervention (MBI) outcomes. Despite its centrality in MBIs, recent reviews have documented limited and mixed effects of home practice on MBI outcomes. However, methodological issues regarding monitoring and quantifying home practice and focus on cumulative or additive effects may limit our understanding of it. Temporally proximate, more transient, and contextually circumscribed effects of mindfulness mediation practice have not been examined. METHODS: We applied intensive experience sampling to measure daily practice and levels of targeted proximal outcomes (state mindfulness, decentering, emotional valance, and arousal) of training over the course of a 21-day MBI among a community-based sample of 82 meditation-naive adults. RESULTS: Despite intensive experience sampling, we found no evidence of cumulative or additive effects of total mindfulness meditation practice on outcomes at postintervention for mindfulness, decentering, emotional valence, or emotional arousal. However, we found that that daily dose of mindfulness meditation home practice significantly predicted same-day levels of state mindfulness (B = 0.004, SE = 0.001, t = 3.17, p = .000, f2 = 0.24), decentering (B = 0.004, SE = 0.001, t = 2.757, p = .006, f2 = 0.05), and emotional valence (B = 0.006, SE = 0.003, t = 2.015, p = .044, f2 = 0.01) but not daily levels of emotional arousal. Daily dose-response practice effects did not carry over to next-day levels of monitored outcomes. CONCLUSIONS: Findings show that effects of daily home mindfulness meditation practice dose on state mindfulness, decentering, and positive emotion are reliable but transient and time-limited. Findings are discussed with respect to the proposed daily dose-response hypothesis of mindfulness meditation practice.

Decentering in the process of cultivating mindfulness: An experience-sampling study in time and context.

OBJECTIVE: Through intensive experience sampling, we studied the practice and development of mindfulness as a dynamic process in time and context. We focused on role(s) and salutary function(s) of mindfulness and decentering for emotional experience over the course of mindfulness practice and development. METHOD: Eighty-two meditation-naive adults from the general community, 52% women, Mage (SD) = 25.05 (3.26) years, participated in a 1-month, 6-session, Mahasi-based mindfulness-training intervention (Mahasi, 1978). We collected 52 digital experience samples of mindfulness, decentering, and emotional experience, in the context of daily living and meditative states, over the course of the program. RESULTS: Data were analyzed via time-varying effects models (TVEMs) and mixed-linear models (MLMs) within a single-subject, multiple-baseline experimental design. First, over the course of the intervention, participants grew more mindful and decentered in daily living and meditative states. Second, the association between mindfulness and decentering was significant in daily living, although the magnitude of this association was stronger in meditative states. Third, we observed the same contextualized pattern of relations between mindfulness and emotional valence (happy > sad) as well as arousal (calm > nervous). Finally, whereas decentering mediated the effect of mindfulness on reduced emotional arousal in meditative states, it did not similarly mediate the effect of mindfulness on positive emotional valence. CONCLUSIONS: The present findings illustrate the insights that may be gained about mindfulness mechanisms broadly and decentering specifically through the study of mindfulness as a dynamic, contextualized developmental process over time. (PsycINFO Database Record

Transport of membrane-bound mineral particles in blood vessels during chicken embryonic bone development.

During bone formation in embryos, large amounts of calcium and phosphate are taken up and transported to the site where solid mineral is first deposited. The initial mineral forms in vesicles inside osteoblasts and is deposited as a highly disordered calcium phosphate phase. The mineral is then translocated to the extracellular space where it penetrates the collagen matrix and crystallizes. To date little is known about the transport mechanisms of calcium and phosphate in the vascular system, especially when high transport rates are needed and the concentrations of these ions in the blood serum may exceed the solubility product of the mineral phase. Here we used a rapidly growing biological model, the chick embryo, to study the bone mineralization pathway taking advantage of the fact that large amounts of bone mineral constituents are transported. Cryo scanning electron microscopy together with cryo energy dispersive X-ray spectroscopy and focused-ion beam imaging in the serial surface view mode surprisingly reveal the presence of abundant vesicles containing small mineral particles in the lumen of the blood vessels. Morphologically similar vesicles are also found in the cells associated with bone formation. This observation directly implicates the vascular system in solid mineral distribution, as opposed to the transport of ions in solution. Mineral particle transport inside vesicles implies that far larger amounts of the bone mineral constituents can be transported through the vasculature, without the danger of ectopic precipitation. This introduces a new stage into the bone mineral formation pathway, with the first mineral being formed far from the bone itself.