Meditation, long celebrated as a path to tranquility, stress relief, and self-understanding, is now central to millions of lives globally and increasingly recommended by clinicians for anxiety and depression. Yet, recent research from Harvard Medical School’s Meditation Research Program uncovers a more complicated reality: for a significant number of practitioners, meditation can generate unsettling or even distressing experiences, sparking crucial new conversations in the mental health and wellness fields (Harvard Gazette).
This development is particularly significant as meditation becomes further embedded in the health and wellness culture of Thailand. In a society where meditation is rooted in Buddhist history and routinely practiced in urban wellness centers, rural temples, and school curriculums, the revelations from this research invite a fresh look at guidance and support for those pursuing meditative practices.
The study, led by the director of Harvard’s Meditation Research Program and published in Clinical Psychological Science in 2025, surveyed over 3,000 adults about their meditation experiences. While the well-established benefits of meditation—alleviating stress, regulating emotions, and bolstering attention—were again affirmed, researchers were surprised by just how common “altered states of consciousness” and subsequent hardship were. According to the findings, 45% of participants reported experiencing altered states related to meditation at least once, with these episodes often described as mystical, spiritual, or magical. Strikingly, 13% reported moderate to severe suffering that followed, ranging from perceptual changes and fear to emotional distress significant enough to warrant clinical care.
These phenomena, often overlooked in modern scientific literature yet noted in traditional meditation texts, are not rare or peripheral. The altered states included out-of-body experiences, changes in sense of size, intense energetic sensations, and disruptions in one’s sense of self. The director of the Harvard program commented, “These kinds of experiences are surprisingly widespread,” emphasizing the urgent need to pay greater attention to these outcomes both in research and in clinical practice.
Importantly, the research went further to identify who might be most at risk. Individuals who reported attempting to engage in divine, magical, or occult practices, those with a history of psychedelic drug use, and those drawn to contemplating life’s mysteries were all more likely to experience intense altered states and, crucially, higher levels of psychological distress afterward. These same groups also reported increased suffering after their experiences, especially if they engaged in frequent spiritual or meditative practice outside of structured retreats. By contrast, prayer—as a practice—was found to be protective, making participants 40% less likely to encounter reality-distorting episodes.
The research team noted that neither religious identity nor participation in specific meditation retreats had much effect on the probability of experiencing altered states. “Identifying as a Buddhist didn’t matter, but practicing mindfulness of the body did. Being Christian had no impact, while praying lowered the incidence,” the lead researcher explained. This insight challenges assumptions in Thailand and elsewhere that collective retreats or specific faith backgrounds insulate individuals from negative psychological reactions to meditative states.
For the Thai context, where meditation is not only part of spiritual life but also featured increasingly in healthcare, education, and even corporate wellness programs, the implications are broad. A senior official from Thailand’s Department of Mental Health, speaking on the condition of anonymity, noted in recent years that meditation retreats, particularly during the “rains retreat” or Buddhist Lent, attract not only monks but also laypeople seeking peace of mind. However, there have occasionally been reports—often quietly discussed—of participants experiencing confusion, panic, or psychological crisis partway through intensive retreats.
This Harvard-led research brings those whispers into the scientific mainstream and invites Thai policymakers, educators, and healthcare providers to consider new approaches for ensuring the safety and psychological readiness of individuals engaging with these practices. For instance, while compassionate loving-kindness meditations and mindfulness of the body can provoke altered states, the risk of distress is not disproportionately high; yet individuals who engage solo and outside structured contexts seem more vulnerable. This underscores the value of community and experienced guidance—a principle that has always been present in the monastic training model widely practiced in Thailand’s temples.
Thai culture offers a wealth of traditional wisdom about spiritual experience, often encapsulated in folk sayings and temple advice suggesting the importance of “kalyāṇa-mitta” (good spiritual friends) when undertaking deep meditative practice. An abbot of a prominent Bangkok monastery, who frequently consults with foreign visitors and lay meditators, has long advocated for the role of mentors and seniors to help practitioners process unusual or difficult experiences during meditation. “The mind can go to many strange places. You need someone wise by your side,” explained the abbot in a recent televised dhamma talk.
Notably, the Harvard research suggests that challenging meditation experiences aren’t necessarily detrimental to long-term growth. In fact, the director of the research program reflected, “Real growth may happen when facing such challenges.” This resonates with Thai Buddhist teachings that framing and working through suffering—“dukkha”—is essential to the path of enlightenment, rather than something to be universally avoided.
Still, the study underscores that dismissing reports of fear, confusion, or psychological suffering as mere “rites of passage” can be risky and harmful. The researchers urge clinicians and meditation teachers alike to recognize the reality of distressing experiences and to offer support without judgment, helping individuals integrate difficult episodes into their worldview. In practice, this may mean training more healthcare professionals to identify when a meditation experience has become overwhelming, developing guidelines for screening who may be vulnerable prior to retreats, or making mental health professionals more available during these intensive practices.
Looking ahead, Harvard’s Meditation Research Program plans to delve further into which personality types, mental health backgrounds, or life circumstances pose the greatest risks—and potentially which forms of meditative practice can be tailored to minimize harm without forgoing the power of genuine spiritual experience. The research team’s ultimate goal is to “bring scientific rigor to a field that has long been understudied.” As the director concluded, “Now we know that these experiences are not unusual at all, and too important to be ignored by science.”
For Thai readers actively engaging in meditation—whether as part of a spiritual journey, a health regimen, or simple daily stress release—this research offers both reassurance and a call to mindfulness (in every sense of the word). Rather than shying away from integration of meditation into schools, hospitals, and workplaces, Thailand can take the lead with evidence-based guidelines and culturally sensitive support systems. For individuals considering deeper exploration, practical steps include seeking instruction from experienced teachers, meditating in community, discussing any unusual or uncomfortable experiences openly, and knowing when to reach out to mental health professionals.
To sum up, meditation remains a powerful tool for well-being—and, as this landmark study reveals, a complex journey that occasionally leads into unexpected territory. Bringing these conversations into the open with compassion and curiosity may be just as important as the calm that meditation so often brings.