Meditation’s Adverse Effects: Willoughby Britton and the Study That Changed Everything

Language: en

Overview

For two decades, the Western mindfulness movement sold meditation as a universal good — a practice with no side effects, no contraindications, and no risks. The marketing was relentless: meditation reduces stress, lowers blood pressure, improves focus, boosts immunity, increases empathy, enhances creativity, and promotes happiness. The science seemed to support the claims — thousands of studies documented meditation’s benefits, and the media amplified each finding into a headline. Meditation was the aspirin of the mind: safe, effective, available to all.

Then Willoughby Britton published her research, and the story got complicated.

Britton, a clinical psychologist and neuroscientist at Brown University, launched the “Varieties of Contemplative Experience” (VCE) project — the first large-scale, systematic, peer-reviewed investigation of meditation-related adverse effects. Her findings, published in a landmark 2017 paper in PLOS ONE (with co-investigator Jared Lindahl), documented that meditation can produce significant negative effects in a substantial minority of practitioners — effects that include depersonalization, derealization, anxiety, panic, emotional instability, insomnia, cognitive impairment, psychotic-like symptoms, suicidal ideation, and prolonged functional impairment.

The study did not claim that meditation is dangerous. It claimed something more nuanced and more important: that meditation is a powerful technique that reliably produces profound changes in consciousness, and that some of those changes — particularly when they occur in vulnerable individuals, without adequate support, or without the practitioner’s understanding of what is happening — can be destabilizing, distressing, and clinically significant. The study that broke the “meditation is always good” myth did not replace it with “meditation is always bad.” It replaced it with “meditation is always powerful — and power requires respect, informed consent, and adequate support.”

In the Digital Dharma framework, Britton’s research is the safety data sheet for the consciousness upgrade — the document that describes not just the benefits of the new firmware but the potential complications, the contraindications, the side effects, and the emergency procedures. Every responsible technology company publishes safety data. The mindfulness industry, until Britton, had not.

The Researcher: From Practitioner to Scientist

Britton’s Personal Motivation

Willoughby Britton’s interest in meditation-related adverse effects was not merely academic — it was personal. As a graduate student at the University of Arizona, she attended an intensive meditation retreat and experienced profound depersonalization, emotional instability, and existential terror that lasted for months after the retreat ended. She sought help from her meditation teachers, who dismissed her experience (“just keep practicing”), and from mental health professionals, who had no framework for understanding it. She eventually navigated the crisis through her own resources, but the experience left her determined to ensure that other practitioners would not face the same lack of support.

Her scientific career has been dedicated to two complementary projects: understanding the mechanisms by which meditation produces its effects (both beneficial and adverse), and building the clinical infrastructure to support practitioners who experience difficulties.

The Academic Context

Britton’s work emerged against a background of what some researchers have called “meditation science’s replication crisis.” By the 2010s, meditation research had produced thousands of studies — but many suffered from methodological weaknesses: small sample sizes, lack of active control groups, self-selection bias (people who like meditation are more likely to sign up for meditation studies), expectation effects (participants expect meditation to help and report accordingly), and publication bias (positive results are published; null results are filed away).

More fundamentally, the meditation research enterprise had a structural blind spot: it looked almost exclusively for benefits. Study designs were structured to detect positive effects. Adverse effects were not systematically assessed, not because researchers were dishonest but because the assumption that meditation is benign was so deeply embedded that the question “does meditation cause harm?” was rarely asked.

Britton asked it.

The Varieties of Contemplative Experience Study

Methodology

The VCE study used a qualitative interview methodology to identify and categorize meditation-related challenging experiences. Between 2013 and 2017, Britton and Lindahl conducted in-depth interviews with 100 meditation practitioners (60 with Western Buddhist background, 32 teachers, and the rest from various traditions) who reported challenging, difficult, or functionally impairing experiences related to their meditation practice.

The interviews were semi-structured, typically lasting 90-120 minutes, and covered the phenomenology of the experience, its duration and intensity, the context in which it arose, the support available, and the ultimate outcome. The interviews were recorded, transcribed, and analyzed using grounded theory — a qualitative research method that develops theoretical categories from the data rather than imposing pre-existing categories on it.

This methodology was deliberate. Britton needed to let the data speak for itself, because no existing framework adequately captured the range of meditation-related difficulties. The DSM-5 has no category for “meditation-related adverse effects.” The Buddhist contemplative literature has maps (the dark night, the dukkha nanas) but they are not designed for clinical application. A new taxonomy was needed, and it had to be built from the ground up.

The Seven Domains of Challenging Experience

The VCE study identified 59 distinct categories of challenging meditation-related experiences, organized into seven domains:

1. Cognitive domain:

• Changes in worldview or beliefs (loss of previously held beliefs, existential questioning)
• Delusional or irrational thoughts
• Thought disturbance (racing thoughts, inability to stop thinking, or conversely, complete absence of thought)
• Difficulty concentrating

2. Perceptual domain:

• Visual disturbances (flashing lights, geometric patterns, distortion of visual field)
• Auditory changes (tinnitus, internal sounds, hearing voices)
• Changes in time perception (time speeding up, slowing down, or stopping)
• Heightened sensory sensitivity (sounds seeming painfully loud, light painfully bright)
• Depersonalization (the sense that the self is not real, that one is observing oneself from the outside)
• Derealization (the sense that the world is not real, that reality has a dreamlike quality)

3. Affective (emotional) domain:

• Anxiety (often intense, often without specific object)
• Fear (existential, primal, sometimes described as “fear of annihilation”)
• Panic attacks
• Sadness and grief (often intense and apparently causeless)
• Emotional blunting (inability to feel emotions, emotional flatness)
• Emotional lability (rapid cycling between emotions)
• Increased emotional sensitivity (feeling others’ emotions, being overwhelmed by emotional stimuli)
• Re-experiencing of trauma (meditation bringing up traumatic memories with full emotional intensity)

4. Somatic domain:

• Changes in body sensations (tingling, burning, pressure, heaviness)
• Changes in sleep (insomnia, hypersomnia, vivid dreams, disturbed sleep architecture)
• Fatigue and exhaustion
• Changes in appetite
• Pain (headaches, chest pain, body pain)
• Involuntary movements

5. Conative (motivational) domain:

• Loss of motivation (inability to engage in work, relationships, or activities)
• Loss of agency (feeling that actions are happening without volition)
• Changes in desire (loss of desire for previously enjoyed activities, food, sex, social contact)
• Aversion to meditation (wanting to stop but feeling unable to, or being told by teachers that stopping would be harmful)

6. Sense of self domain:

• Changes in self-perception (feeling that the self is dissolving, changing, or not real)
• Changes in narrative identity (loss of the story of “who I am”)
• Boundary changes (difficulty distinguishing self from other, inner from outer)
• Loss of foundational sense of self (the basic sense of “I am” becomes unstable or absent)

7. Social domain:

• Impaired social functioning (difficulty relating to others, feeling alienated)
• Relationship disruption (partners, friends, and family not understanding the experience)
• Professional impairment (inability to work, loss of career motivation)
• Social withdrawal (desire to be alone, inability to tolerate social situations)

Key Findings

Prevalence: While the VCE study was not designed to measure prevalence (it used a self-selected sample of practitioners who reported difficulties), other studies have estimated that 6-14% of meditators experience significant adverse effects. A 2020 study by Marco Schlosser and colleagues at University College London found that 25% of regular meditators reported unpleasant experiences, with 8% reporting experiences that were distressing enough to impair daily functioning.

Duration: The duration of adverse effects varied enormously. Some practitioners reported effects lasting days or weeks; others reported effects lasting months or years. A subset of practitioners reported effects that were still ongoing at the time of the interview, years after the triggering meditation experience.

Practice factors: The VCE study found that adverse effects were associated with certain practice factors: intensive retreat practice (longer retreats, more hours per day), concentration-heavy practices (jhana-oriented practices that produce intense states), and practices done without adequate teacher guidance. However, adverse effects also occurred in practitioners with modest practice levels and good teacher support — suggesting that practice factors are contributing but not sufficient causes.

Personal factors: Pre-existing trauma, mental health conditions (particularly anxiety disorders, mood disorders, and dissociative tendencies), and a history of childhood adversity were associated with increased vulnerability to adverse effects. This does not mean that people with mental health conditions should not meditate — it means they should be screened, monitored, and supported more carefully.

Contextual factors: The availability of knowledgeable support was the single most important factor in determining whether adverse effects became chronic or resolved. Practitioners who had access to teachers or therapists who understood the territory moved through difficulties more quickly and with less lasting impairment than those who were told to “just keep practicing” or who were misdiagnosed with psychiatric illness.

Cheetah House: From Research to Clinical Support

Building the Safety Net

In response to her research findings, Britton founded Cheetah House — a nonprofit organization based in Providence, Rhode Island, that provides free support to meditators experiencing practice-related difficulties. Cheetah House offers:

• A hotline staffed by trained volunteers and clinicians
• Individual consultations with clinicians experienced in meditation-related difficulties
• Peer support groups for meditators in distress
• Training for meditation teachers in recognizing and responding to adverse effects
• Training for mental health professionals in distinguishing meditation-related experiences from psychiatric illness
• Educational resources for the meditation community

Cheetah House represents the practical translation of Britton’s research into clinical action — the creation of the safety infrastructure that the mindfulness industry should have built from the beginning.

The Contemplative Map: Connecting Britton to the Tradition

What the Buddhist Tradition Already Knew

Perhaps the most striking aspect of Britton’s findings is how precisely they map onto the traditional Buddhist description of the dark night (dukkha nanas) described in the Progress of Insight. The VCE study’s seven domains of challenging experience are nearly identical to the phenomenology of the dark night stages:

• Dissolution nana → depersonalization, derealization, perceptual disturbances
• Fear nana → anxiety, panic, existential terror
• Misery nana → depression, loss of motivation, existential despair
• Disgust nana → aversion to practice, aversion to life, emotional blunting
• Desire for Deliverance → desperate desire to escape the experience

Britton herself has noted this correspondence. Her interpretation is that the traditional maps are broadly accurate — the dark night is a genuine, predictable phase of contemplative development — but that the traditional frameworks underestimate its severity in some practitioners and provide inadequate clinical guidance for those who become stuck in it.

The traditional Theravada response to the dark night is “keep practicing — push through to equanimity.” This advice is appropriate for experienced meditators on intensive retreat with qualified teachers. It is potentially harmful when applied to casual meditators, meditators with pre-existing mental health conditions, or meditators who are not on retreat and do not have intensive teacher support.

The Gap Between Traditional and Modern Contexts

The traditional contemplative context is radically different from the modern mindfulness context in ways that are clinically significant:

Traditional context: Full-time practice. Monastic community. Daily access to a qualified teacher. Decades of gradual preparation before intensive practice. Comprehensive ethical framework (sila). Concentration practice established before insight practice. Community support. Cultural understanding of the territory.

Modern context: Part-time practice. No community (or a loose, self-selected community). Intermittent teacher contact (a weekly class, an annual retreat). Minimal preparation before jumping into intensive practice. No ethical framework (or a vague, self-defined one). Insight practice without adequate concentration foundation. Social isolation. No cultural understanding of the territory.

The same practices that produce safe, transformative results in the traditional context can produce destabilizing, harmful results in the modern context. The practice is the same. The container is radically different. And the container matters enormously.

Implications for the Mindfulness Industry

Informed Consent

Britton has argued forcefully that meditation instruction should include informed consent — explicit information about potential adverse effects, provided before practice begins. This is standard practice in medicine (every medication comes with a list of side effects), in psychotherapy (every therapeutic approach has known risks), and in research (every study protocol includes informed consent). That the mindfulness industry has not adopted this practice reflects not a judgment that meditation is risk-free but a marketing decision that disclosing risks would reduce enrollment.

The informed consent should include:

• Meditation can produce temporary distress (anxiety, emotional instability, perceptual changes) in some practitioners.
• In a small but significant minority, these effects can be severe and prolonged.
• Pre-existing mental health conditions may increase vulnerability.
• Intensive practice (retreats, long sessions) carries higher risk than moderate practice.
• If distressing symptoms arise, the practitioner should contact their teacher and consider clinical consultation.
• The experience may correspond to recognized stages of contemplative development that, while difficult, are generally transient and ultimately beneficial when properly supported.

Teacher Training

Most meditation teacher training programs do not include systematic instruction in recognizing and responding to adverse effects. This is a critical gap. Teachers are the front line — they are the first point of contact when a student experiences difficulties. If the teacher does not recognize the phenomenon, the student may be told that nothing is wrong (“just keep practicing”), which can prolong the difficulty, or may be told that something is very wrong (“you need psychiatric help”), which can pathologize a normal contemplative experience.

Britton has developed a teacher training curriculum called the “First, Do No Harm” program that covers:

• The phenomenology of meditation-related adverse effects
• Risk factors (pre-existing conditions, practice intensity, lack of support)
• Screening and assessment protocols
• When to modify practice, when to stop practice, and when to refer for clinical support
• The distinction between challenging-but-productive contemplative experience and genuinely harmful adverse effects

Research Reform

Britton’s work has implications for meditation research methodology. Studies that assess only benefits and ignore adverse effects produce a distorted picture. Britton has argued that all meditation research should include systematic assessment of adverse effects — using standardized instruments, not just open-ended questions — to build a comprehensive safety profile.

The Meditation Safety Toolbox, developed by Britton and colleagues, provides standardized instruments for assessing meditation-related adverse effects in research settings. Its adoption by the meditation research community would transform our understanding of meditation’s risk-benefit profile.

The Functional Medicine Lens

Individual Variability

Britton’s research resonates deeply with the functional medicine principle that individual variability matters more than population averages. The average meditator benefits from meditation. But the average conceals the range — and at the tails of the distribution, meditation can produce severe harm.

The functional medicine approach to meditation would look like the functional medicine approach to any intervention: thorough assessment of the individual’s baseline (physical health, psychological health, trauma history, current medications, social support), careful selection of the appropriate practice (not all meditation is the same — concentration practices, insight practices, mantra practices, and movement practices have different risk profiles), gradual titration of intensity (starting with small doses and increasing as tolerance develops), ongoing monitoring (regular check-ins with a knowledgeable provider), and immediate response to adverse effects (modify the practice, provide support, or discontinue if necessary).

This is radically different from the current model, in which meditation is prescribed as a one-size-fits-all intervention with no screening, no titration, no monitoring, and no safety protocol. The current model is the equivalent of prescribing a powerful medication without checking for allergies, starting at full dose, not scheduling follow-up, and having no plan for adverse reactions.

The Shamanic Wisdom

Indigenous healing traditions have always understood that powerful consciousness-altering practices carry risks. The shamanic apprentice does not undertake a vision quest without years of preparation, the guidance of an elder shaman, and the support of the community. The ayahuasca ceremony includes careful screening (no one with a history of psychosis is allowed to participate), preparation (dietary restrictions, intention-setting), supervision (the curandero monitors every participant throughout the ceremony), and integration (post-ceremony discussion and support).

Modern mindfulness has stripped meditation of all these safety features — the screening, the preparation, the supervision, the integration — and presented the bare technique as safe for universal application. Britton’s research reveals the predictable consequence: a minority of practitioners are being harmed by a practice that, with appropriate safeguards, could be transformative.

The shamanic wisdom is not that powerful practices should be avoided. It is that powerful practices should be respected — approached with preparation, guided by experience, supported by community, and held in a container strong enough to handle the forces that are unleashed.

Conclusion

Willoughby Britton’s research on meditation-related adverse effects is not an indictment of meditation. It is a maturation of the conversation — a shift from the naive position (“meditation is always good”) to the informed position (“meditation is a powerful practice that, like all powerful practices, requires respect, informed consent, and adequate support”).

The 6% figure — the proportion of meditators who experience significant adverse effects — is both reassuring (the vast majority of meditators benefit) and sobering (millions of people meditate, and 6% of millions is a substantial number of individuals experiencing potentially serious harm). The solution is not to abandon meditation but to build the safety infrastructure that the practice demands: informed consent, teacher training, clinical protocols, and research that takes both benefits and risks seriously.

Britton’s work is the beginning of that infrastructure. Cheetah House is the first clinical service. The VCE taxonomy is the first diagnostic framework. The “First, Do No Harm” program is the first teacher training curriculum. These are the foundations on which a responsible, evidence-based, safety-conscious meditation culture can be built.

The firmware update works. It works beautifully for most users. But for some users, under some conditions, the installation process produces complications that require professional support. Britton has given us the safety data, the diagnostic tools, and the clinical protocols to provide that support. The question now is whether the mindfulness industry will adopt them — or continue to sell the upgrade without mentioning the error log.