The Effects of Intensive Mindfulness Meditation Training on Mental Health: Evidence of Effectiveness and Safety from a Matched-Controlled Retreat Intervention Study

Despite increased public interest and research on intensive high-dose mental health interventions, much remains unknown about the mental health effects and safety of multi-day intensive high-dose mindfulness meditation training. Accordingly, we aimed to study its salutary and adverse effects on mental health. We conducted a preregistered prospective intervention study among 89 adults who registered for 6-day insight mindfulness meditation retreats and 46 matched controls (Mage(SDage) = 33.75(9.50), 56.3% female). Controls were selected from a pool of 543 people recruited from the same community of meditators as retreat participants and matched to retreat participants on age and lifetime meditation experience. Retreat participants demonstrated significant improvements in well-being, negative affect, perseverative thinking, brooding rumination, and depression symptoms at 2-week follow-up compared to matched controls (η² range = .04–.08, ps < .05). Importantly, the % of participants exhibiting statistically reliable deterioration in mental health outcomes at 2-week follow-up were equal or lower among retreat participants than among matched controls in the entire sample, as well as in a sub-sample with clinically elevated depression and/or anxiety (ORs < 1). These findings suggest that a 6-day mindfulness meditation retreat can produce rapid improvements in mental health, comparable to effect sizes of much longer 8-week mindfulness-based programs. These findings also challenge concerns about adverse effects of intensive high-dose meditation training and suggest that it may be a safe and effective intervention modality, even for clinically vulnerable adults struggling with depression or anxiety.