Background Mindfulness-based interventions are increasingly being implemented worldwide for problems with depression and anxiety, and they have shown evidence of efficacy. However, few studies have examined the effects of a mindfulness-based group therapy based on standard programs for depression and anxiety until follow-up in Japan. This study addresses that gap. Furthermore, this study explored the mechanisms of action, focusing on mindfulness, mind wandering, self-compassion, and the behavioral inhibition and behavioral activation systems (BIS/BAS) as possible mediators. Methods We examined 16 people who suffered from depression and/or anxiety in an 8-week mindfulness group therapy. Measurements were conducted using questionnaires on depression and trait-anxiety (outcome variables), mindfulness, mind wandering, self-compassion, and the BIS/BAS (process variables) at pre- and post-intervention and 2-month follow-up. Changes in the outcome and process variables were tested, and the correlations among the changes in those variables were explored. Results Depression and anxiety decreased significantly, with moderate to large effect sizes, from pre- to post-intervention and follow-up. In process variables, the observing and nonreactivity facets of mindfulness significantly increased from pre- to post-intervention and follow-up. The nonjudging facet of mindfulness and self-compassion significantly increased from pre-intervention to follow-up. Other facets of mindfulness, mind wandering, and the BIS/BAS did not significantly change. Improvements in some facets of mindfulness and self-compassion and reductions in BIS were significantly correlated with decreases in depression and anxiety. Conclusions An 8-week mindfulness group therapy program may be effective for people suffering from depression and anxiety in Japan. Mindfulness and self-compassion may be important mediators of the effects of the mindfulness group therapy. Future studies should confirm these findings by using a control group. Trial registration University Hospital Medical Information Network (UMIN CTR) UMIN000022966. Registered July 1, 2016, https://upload.umin.ac.jp/cgi-open-bin/ctr/ctr_view.cgi?recptno=R000026425

Recent studies have suggested that sensory-processing sensitivity correlates to poor psychological and physical health. However, it remains unclear how this occurs. Sensory-processing sensitivity can be understood as sensitivity to sensations without the presence of intentional awareness and a nonreactive attitude, which are the components of mindfulness. We tested the hypothesis that dispositional mindfulness mediates the relationship between sensory-processing sensitivity and trait anxiety, well-being and psychosomatic symptoms. We analyzed data from 563 participating young adults living in Japan. Multiple mediation analysis showed that the four facets (nonreactivity, nonjudging, describing, and acting with awareness) of mindfulness partially mediated the effects of sub-factors of sensory-processing sensitivity (low sensory threshold and ease of excitation) on trait anxiety. Nonreactivity, describing, and acting with awareness partially mediated the effect of low sensory threshold on well-being and fully mediated the effect of ease of excitation. Nonjudging and acting with awareness partially mediated the effects of low sensory threshold and ease of excitation on psychosomatic symptoms. As a whole, the mediation hypotheses were supported, and it was determined that the improvement of dispositional mindfulness may prove effective for the psychological and physical problems of people with high sensory-processing sensitivity.

Mind-wandering (MW), task-unrelated thought, has been examined by researchers in an increasing number of articles using models to predict whether subjects are in MW, using numerous physiological variables. However, these models are not applicable in general situations. Moreover, they output only binary classification. The current study suggests that the combination of electroencephalogram (EEG) variables and non-linear regression modeling can be a good indicator of MW intensity. We recorded EEGs of 50 subjects during the performance of a Sustained Attention to Response Task, including a thought sampling probe that inquired the focus of attention. We calculated the power and coherence value and prepared 35 patterns of variable combinations and applied Support Vector machine Regression (SVR) to them. Finally, we chose four SVR models: two of them non-linear models and the others linear models; two of the four models are composed of a limited number of electrodes to satisfy model usefulness. Examination using the held-out data indicated that all models had robust predictive precision and provided significantly better estimations than a linear regression model using single electrode EEG variables. Furthermore, in limited electrode condition, non-linear SVR model showed significantly better precision than linear SVR model. The method proposed in this study helps investigations into MW in various little-examined situations. Further, by measuring MW with a high temporal resolution EEG, unclear aspects of MW, such as time series variation, are expected to be revealed. Furthermore, our suggestion that a few electrodes can also predict MW contributes to the development of neuro-feedback studies.

While dichotic listening (DL) was originally intended to measure bottom-up selective attention, it has also become a tool for measuring top-down selective attention. This study investigated the brain regions related to top-down selective and divided attention DL tasks and a 2-back task using alphanumeric and Japanese numeric sounds. Thirty-six healthy participants underwent near-infrared spectroscopy scanning while performing a top-down selective attentional DL task, a top-down divided attentional DL task, and a 2-back task. Pearson's correlations were calculated to show relationships between oxy-Hb concentration in each brain region and the score of each cognitive task. Different brain regions were activated during the DL and 2-back tasks. Brain regions activated in the top-down selective attention DL task were the left inferior prefrontal gyrus and left pars opercularis. The left temporopolar area was activated in the top-down divided attention DL task, and the left frontopolar area and left dorsolateral prefrontal cortex were activated in the 2-back task. As further evidence for the finding that each task measured different cognitive and brain area functions, neither the percentages of correct answers for the three tasks nor the response times for the selective attentional task and the divided attentional task were correlated to one another. Thus, the DL and 2-back tasks used in this study can assess multiple areas of cognitive, brain-related dysfunction to explore their relationship to different psychiatric and neurodevelopmental disorders.

The mechanisms of efficacy in mindfulness-based interventions for depression and anxiety are not fully understood. To clarify these mechanisms, we tested the hypotheses that mind-wandering, daydreaming, cognitive fusion, and experiential avoidance will decrease through mindfulness group therapy, and this decrease will correlate with improvements in depression and anxiety. Participants self-reported depression and/or anxiety (N = 28) took part in an 8-week mindfulness group therapy program. They were assessed using self-report scales at pre- and post-intervention, and at 2-month follow-up. Results indicated that depression and trait-anxiety decreased between pre- and post-intervention with moderate effect sizes, which were maintained at follow-up. Mind-wandering and cognitive fusion also decreased between pre- and post-intervention with small to moderate effect sizes, and maintained at follow-up. The decreases in mind-wandering and cognitive fusion moderately correlated with improvements in depression and anxiety, suggesting that decreases in mind-wandering and cognitive fusion might underlie efficacious mechanisms of mindfulness group therapy.