Background — Our previous study revealed that mindfulness might reduce anger rumination. However, no study has examined the effects of mindfulness training focusing on anger rumination. Anderson et al. (2007) provided the initial evidence for the effects of mindfulness training on anger rumination. The results suggested that mindfulness training significantly reduced anger rumination. Though this preliminary intervention study revealed that mindfulness training was effective for anger rumination, its effects on more important anger-related problems such as trait anger remain unclear.
Aims — To examine whether anger rumination and trait anger are reduced after receiving a brief mindfulness training.
Methods — Japanese undergraduates (N = 8, M age = 19.40 years, SD age = 1.71 years, range = 18–23 years; 4 females) participated in a brief mindfulness training program. Although exclusion criteria were having major depression disorder or bipolar disorder, no one met the criteria. All participants received 5-week mindfulness training including psychoeducation on anger, raisin exercise, sitting meditation, and mindfulness of breath. The questionnaires focused on mindfulness (Five Facets of Mindfulness Questionnaire, FFMQ; Baer et al., 2006), anger rumination (Anger Rumination Scale, ARS; Sukhodolsky et al., 2001), and trait anger (State Trait Anger Expression Inventory, STAXI; Spielberger, 1988). All questionnaires were assessed pre- and post-intervention. Additionally, ARS and STAXI were also assessed after each session. The project was carried out in accordance with the protocol approved by The Ethics Board of Psychological Research of Kansai University. All participants provided informed consent.
Results — Intent-to-treat analysis (N = 8) revealed that no subscale of FFMQ showed significant increase (Observing, d = 0.53; Describing, d = 0.00; Nonjudging of inner experience, d = 0.41; Nonreactivity to inner experience, d = 0.24; Acting with Awareness, d = -0.38). There were significant reductions in anger rumination (Tau = -0.50, p < .001; d = -1.35) and trait anger (Tau = -0.48, p < .001; d = - 0.69).
Conclusions — This study revealed that mindfulness training reduced anger rumination and trait anger. Although mindfulness training in this study was a brief intervention (5 session), the magnitude of its effect on anger rumination was equal to that of Anderson et al.’s (2007) study. However, effect sizes for mindfulness subscales were relatively small, suggesting that a brief mindfulness training might be insufficient to enhance mindfulness skills. Randomized control trial with sufficient sample size is necessary to explore its effects on anger-related problems and the underlying mechanism.