The study matters because meditation training has exploded far beyond monasteries and meditation centers. It is now embedded in psychotherapy clinics, hospitals, schools, and corporate wellness programs, and surveys suggest tens of millions of adults practice some form of it. Alongside that growth, a serious scientific conversation has emerged about unintended harm. Researchers have documented meditation-related experiences ranging from time-limited anxiety and traumatic re-experiencing to, in rarer cases, lasting problems such as executive dysfunction, delusional beliefs, hallucinations, depression, and insomnia. Just as potent psychological or pharmacological therapies can produce adverse effects, the argument goes, so can meditation, and clinicians need to know who is most at risk.

Until now, the evidence pointing to mental health symptoms as a risk factor came largely from retrospective, cross-sectional surveys. In those studies, meditators with substantial prior experience, often more than one hundred lifetime hours, reported on past symptoms and past distressing experiences, sometimes months or years after the fact. Such designs suffer from well-known recall biases, and, critically, they lack a comparison group of non-meditators. Without knowing the base rate of distressing experiences in daily life, it is impossible to say whether difficult experiences during meditation are caused by the practice or simply reflect what people with elevated symptoms experience anyway. A person prone to anxiety may report intense anxiety during a retreat, but they may also report intense anxiety during an ordinary week at home.

A handful of prospective studies tried to address the recall problem by measuring symptoms before mindfulness-based interventions and tracking outcomes afterward, with mixed results. But those studies typically involved moderate practice doses, from zero to forty-five minutes a day over four to eight weeks, and were designed as treatments tailored to people with mental health difficulties. None included a non-meditation control group. The highest-intensity common format, the residential retreat, with six to eleven hours of daily practice in a secluded setting, remained comparatively underexamined, even though prior work suggests most distressing or impairing meditation-related experiences begin during or shortly after retreats.

The new study, a secondary analysis of a trial preregistered at ClinicalTrials.gov in December 2020, tackled these limitations with a prospective matched-control design. Eighty-nine participants enrolled in one of five six-day residential insight (Vipassana) retreats run by the Tovana Israel Insight Meditation Society, while forty-four controls were drawn from the same meditation community and matched on age and lifetime meditation experience. The retreat schedule was demanding: at least ten roughly forty-five-minute sessions of sitting and walking meditation per day, totaling a minimum of seven and a half hours of formal practice, embedded in silence, alongside loving-kindness sessions, mindful movement, and mindful work periods. Teachers gave daily talks and small-group interviews, and participants progressively shifted from focused-attention practice to broader, deconstructive awareness practices.

Before the retreats began, all participants completed the Patient Health Questionnaire-9 for depression and the Overall Anxiety Severity and Impairment Scale for anxiety. During the retreat, or an equivalent six-day window for controls, they filled out the Peak Meditative Experience Scale, reporting on thirty-two unusual, intense experiences and rating each one’s hedonic tone from extremely unpleasant to extremely pleasant. Nine items, including intense anxiety, flashbacks, and overwhelming sadness, had previously been identified as predominantly unpleasant. Two weeks after the retreat, participants rated both the positive and negative impact of each endorsed unpleasant experience, allowing the researchers to compute a net post-retreat impact score. The sample showed wide variability in symptoms, though most participants fell below clinical screening cutoffs, and roughly two-thirds had more than one hundred lifetime meditation hours.

The statistical strategy centered on bootstrapped moderation models testing whether baseline symptoms interacted with group membership in predicting unpleasant experiences. The hypothesis was straightforward: higher symptoms should predict more distressing experiences among retreat participants relative to controls. Instead, the interaction for depression symptoms was significant in the opposite direction. Retreat participants scoring one standard deviation below the mean on depression endorsed significantly more unpleasant peak experiences than matched controls with similar symptoms, while those at or above the mean did not differ from controls. The anxiety results followed the same pattern, with a marginally significant interaction and the same reversal among low-symptom participants. Sensitivity analyses examining the valence, frequency, and duration of unpleasant experiences found no evidence that elevated symptoms increased risk on any dimension, and the findings held after controlling for lifetime meditation hours, retreat days, and gender.

The two-week follow-up added a further twist. The relationship between pre-retreat anxiety and the net impact of distressing experiences was best described by a quadratic curve: participants with both low and high baseline anxiety reported that their unpleasant retreat experiences had, on balance, a more positive than negative impact two weeks later, while those with moderate anxiety showed a net zero difference. Depression symptoms showed no significant relationship with post-retreat impact at all. The authors suggest several interpretations. Low-symptom participants may have been more resilient to begin with, and resilience is linked to evaluating difficult experiences as opportunities for growth. High-symptom participants, meanwhile, may have benefited most, consistent with evidence that people with greater baseline vulnerability often gain more from mindfulness-based interventions. Intensive practice in a supportive setting, with teachers available and instructions emphasizing non-judgment and acceptance, may even function as a form of stress inoculation, teaching practitioners to approach anxiety rather than flee from it.

Perhaps the most consequential implication concerns causation. The study found that greater depression and anxiety symptoms were associated with more unpleasant experiences in both groups, meditators and controls alike. That means the correlations reported in earlier retrospective studies may be real and replicable, but attributable not to meditation itself. Distressing experiences among people with elevated symptoms may simply be part of the background noise of daily life, and intensive practice neither amplifies nor uniquely generates them, at least in this retreat format. The authors argue this demonstrates the necessity of no-meditation control conditions for anyone hoping to attribute distressing experiences or adverse effects to meditation training, a methodological point with echoes of long-standing debates about distinguishing treatment effects from base-rate phenomena in psychotherapy research.

The study has limits the authors are careful to acknowledge. A fully randomized active-control design would provide stronger causal evidence than matching, the sample was not well powered to detect small interaction effects, and most participants fell below clinical thresholds for depression and anxiety, so the findings may not generalize to severely symptomatic clinical populations. The researchers also call for future work on symptoms beyond depression and anxiety, including posttraumatic stress and psychotic symptoms, on longer and more intensive retreat formats, and on replication across retreat centers, traditions, and cultures. Still, if the results hold up in larger and more diverse samples, the clinical message is striking: depression and anxiety symptoms alone may not constitute contraindications to intensive meditation retreat training, and for some practitioners, the difficult moments on the cushion may ultimately be the ones that help the most.

Subject of Research: Whether pre-existing depression and anxiety symptoms predict distressing experiences during intensive mindfulness meditation retreat training

Article Title: Mental Health Symptoms Do Not Increase Risk for Distressing Experiences During Intensive Mindfulness Meditation Training: Evidence from a Prospective Matched-Control Intervention Study

Article References: Mental Health Symptoms Do Not Increase Risk for Distressing Experiences During Intensive Mindfulness Meditation Training: Evidence from a Prospective Matched-Control Intervention Study. (n.d.). https://doi.org/10.1007/s12671-026-02982-9

Image Credits: AI Generated

DOI: 10.1007/s12671-026-02982-9

Keywords: mindfulness, meditation retreats, adverse effects, depression, anxiety, matched-control study, insight meditation, mental health risk factors, Vipassana, clinical psychology, contemplative science, preregistered research