Peak Experiences During Mindfulness Meditation Retreats and Their Salutary and Adverse Impact: A Prospective Matched-Controlled Intervention Study

Objective: We sought to address a growing debate regarding the adverse and salutary impact of unusual, extraordinary, or intense subjective experiences during mindfulness interventions. To do so, we empirically characterized such peak experiences during an intensive mindfulness meditation intervention and their impact post-intervention. Method: We conducted a preregistered prospective intervention study among 96 adults who registered to a six-day mindfulness meditation retreat and 47 matched-controls. Controls were selected from a pool of 487 people recruited from the same community of meditators as retreat participants and systematically matched to retreat group on age and lifetime meditation experience. Measures included the Peak Meditative Experience Scale (PMES) and the Impact of PMES (I-PMES). Results: Seventeen peak experiences that were predominantly pleasant (e.g., deep and unusual peace, aha! moment) occurred more frequently among retreat participants than among matched-controls in daily living (ps < .05; mean φ = .33). In contrast, 14 peak experiences that were mostly unpleasant (e.g., flashbacks, overwhelming sadness) occurred at similar rates in both groups (ps > .05). At two-week follow-up, the perceived impact of all pleasant and most unpleasant peak experiences was more salutary than adverse (ps ≤ .015; M Cohen’s d = 1.61). Conclusions: Peak experiences that resulted from intensive mindfulness meditation training were primarily pleasant and had a large salutary impact post-retreat. Inconsistent with conclusions from uncontrolled studies, findings document that intensive mindfulness meditation training may not contribute to unpleasant peak experiences, and even when they occurred their impact was typically more salutary than adverse.