Negative effects related to meditation have been described across a variety of religious traditions, and in Western psychology. Terms such as ‘Dark Night of the Soul,’ ‘Kundalini Crisis’ and ‘Spiritual Emergence’ have all been used to refer to periods of difficulty associated with contemplative practice. The use of the term ‘adverse effects’ in Western meditation research can be traced back to Leon Otis, who used the term in his 1984 study of TM meditators, and Deane Shapiro who referred to adverse effects in his 1992 study of vipassana meditators. More recently, Lindahl and colleagues have described meditation adverse effects as meditation experiences that are “challenging, difficult, distressing, functionally impairing, and/or requiring additional support.” In their recent study The Varieties of Contemplative Experience, the authors note:
Meditation-related effects that are not health-related benefits or that are reported as distressing have been classified as “side effects” or “adverse effects” (AEs), especially in clinical psychology research.”
In this particular study the authors describe a “taxonomy of 59 meditation-related experiences across 7 domains: cognitive, perceptual, affective, somatic, conative, sense of self, and social.” These experiences range from very positive to very negative.
In Eastern religions, traditional commentaries, stages-of-the-path literature and biographical narratives acknowledge difficulties associated with meditation practice. For example, Eric Greene writes that Buddhist meditation has been seen as both a high risk and high reward practice:
Given its frequent presentation in the modern West as a panacea for psychological or even physical ailments, it might be surprising to find that Buddhist meditation has often been seen as potentially dangerous. The otherwise highly praised Buddhist meditations on the impurity of the body can, according to a famous canonical story, lead to suicide; elsewhere we learn that meditation on the breath-a common introductory meditation practice-can, if performed improperly, disturb the body’s “winds” and lead to death. The Buddha himself is said to have been attacked by demons-in the form of the hosts of Mara-on the eve of his awakening, precisely on account of his advanced levels of meditative attainment.
In Theravada Buddhism, adverse effects associated with meditation are well-known and may be due to the dukkha nanas (Pali: insights into suffering), a series of insights that are characterised by fear, misery and disgust and which can cause mental distress. These experiences are well documented in Buddhist manuals such as the Visuddhimagga (The Path of Purification), the Vimuttimaga (The Path of Freedom), and the Abhidhamma, and are usually interpreted as milestones on the path to enlightenment. Lois VanderKooi provides a concise description of the dukkha nanas:
As outlined in the Visuddhimagga (a fifth-century work that supposedly collects the Buddha’s teachings on meditative states), the process of realising nirvana is fraught with troubling and sometimes excruciating states. Initially, confusion, hallucinations, disturbing feelings, and involuntary movements can occur as one gains knowledge of mental and physical states through increasing concentration and mindfulness. As samadhi is achieved, ‘pseudo-nirvana’ experiences of rapture, tranquillity, and bliss can be accompanied by frightening images, uncomfortable body sensations such as itching, heat, and stiffness, and gastrointestinal problems of nausea, vomiting, and diarrhea. Then, sadness, irritability, extreme fear, and a deep sense of the insipid nature of life may manifest as one becomes more and more aware of the arising and passing away of phenomena. A desire for deliverance can emerge, and one may wish to discontinue practice. For example, the body may itch as though being bitten by ants. Later, when deciding to practice to completion, one may feel odd sensations such as being slashed by a knife.
The samatha-vipassana meditation manual by Sramaṇa Zhiyi (538-597 CE), founder of the Tiantai tradition of Buddhism in China, has a chapter dedicated to the diagnosis and treatment of meditation-related disorders. According to this text, meditation-related pathology may develop as a result of imbalance during practice:
Once the practitioner has established his resolve to cultivating the Path, disorders associated with the four great elements may manifest. Based on one’s present application of the contemplative mind, the breath may be caused to provoke the activation of latent disorders. Sometimes it happens that one is unable to skilfully and appropriately adjust the three factors of body, mind and breath. Due to interferences between the inward and outward circumstances, pathological trouble may develop … if one is able to skilfully apply the mind, then the four hundred and four kinds of disorders will naturally be cured. If, however, one fails in the correct placement of the mind, then the four hundred and four kinds of disorders may arise on that very account.
Adverse effects associated with meditation are also documented in Zen Buddhism. For example, there is a category of meditative experiences that may arise during zazen practice, called makyo (translated as “diabolic phenomenon”, from ma (devil) and kyo (phenomenon; objective world)). Hence, makyo are disturbing phenomena, and can include visual, auditory and olfactory hallucinations and involuntary movements. In The Three Pillars of Zen, American Zen teacher Roshi Philip Kapleau notes that the number of makyo which can appear to a meditator are unlimited; in the Ryogon sutra the Buddha warns of fifty different kinds of makyo, but these are just the most common manifestations, and experiences may vary according to the personality and temperament of the individual meditator.
Zen traditions also acknowledge a prolonged illness-like condition related to meditation, called ‘Zen sickness’ or ‘meditation sickness’. This condition is understood to manifest due to a variety of causes that may be physiological, psychological, karmic, or supernatural in nature. Depending on the cause, Zen sickness may manifest in different ways (for example, as headaches, tightness in the chest or fearful hallucinations), and traditional teachers recommend an assortment of treatments ranging from modern medical and psychological care to traditional mantras, spells and repentance practices.
In Tibetan Buddhism, nyams (meditation experiences) may include adverse effects such as intense body pain, physiological disorders, paranoia, sadness, anger and fear. Additionally, there is a specific meditation-related condition that the Tibetans call lung. Sometimes described as a “nervous disorder” or “meditator’s disease,” there are several different types of lung that are said to result from the interaction between meditation practice and characteristics of the individual meditator, such as imbalances in the meditator’s constitution or their karma. In Balanced Mind, Balanced Body, Amy Cayton describes various treatments for lung, which come from both Tibetan folklore and more experienced meditators from the lay community. These include bodhichitta and tonglen practice, prostrations, mantras, traditional Tibetan medicine, and changes to diet and sleep. Cayton notes that meditators are advised to consult a qualified teacher or Tibetan doctor to treat lung and that without treatment it can become a chronic state that is difficult to deal with. Cayton writes:
When we talk about lung, we must distinguish between acute and chronic lung. In this essay, I’m mainly concerned with acute lung, specifically that which arises in meditation retreats. Acute lung can come from concentrating too hard on the mandala, reciting mantras too fast, working too hard in service or at our jobs, or frustration in relationships. With rest and Tibetan medicine (if we can get it), this form of lung goes away when we finish our retreat or stop doing what was causing our mental stress. Chronic lung, or tsok lung, is what we might label as varying degrees of post-traumatic stress disorder (PTSD). Chronic lung can be treated with herbs, diet, acupuncture, Tibetan medicine, and verbal therapies.
Hindu and Yogic traditions also acknowledge periods of difficulty associated with meditation practice, most often associated with kundalini, which is said to be the biological mechanism behind enlightenment. Classical esoteric literature describes kundalini as a normally dormant force that resides at the base of the spine, and that when awakened, can cause a variety of mental, emotional, physical and spiritual effects. According to Eastern philosophers, kundalini should only be awakened as a gradual process, under the guidance of an experienced teacher. If a kundalini awakening occurs when a meditator is not properly prepared, it can cause negative effects, including fear, disorientation and psychosis. Scholars have argued that because the ancient traditions provided gurus to supervise kundalini awakenings, the classical literature did not focus on problems associated with the phenomena; it was assumed that with proper context and proper guidance, the process would lead to positive outcomes. However, there are modern biographical accounts that report severe problems attributed to kundalini, usually referred to as ‘kundalini crisis.’ The most well-known case is Gopi Krishna (1903 – 1984), an Indian yogi and mystic who wrote about his own long-lasting kundalini crisis which included symptoms of depression, insomnia and psychosis-like states.
Hence, meditation adverse effects are mentioned across a variety of religious traditions. The literature observes that meditation adverse effects may arise simply as a normal stage on the path of progress towards enlightenment (for example, makyo and the dukkha nanas), or if the practice is not undertaken with adequate preparation, in the right conditions and with proper guidance (such as is the case with Zen sickness, lung and kundalini crisis). However, when secular forms of meditation are disconnected from these traditional religious sources, this knowledge regarding adverse effects is often lost.
 L. S. Otis, “Adverse Effects of Transcendental Meditation,” in Meditation: Classic and Contemporary Perspectives, eds. D.H. Shapiro and R. N. Walsh (New York, NY: Aldine Transaction, 2009 ), 201-208.
 D. Shapiro, “Adverse Effects of Meditation: A Preliminary Investigation of Long-term Meditators,” International Journal of Psychosomatics 39 (1992): 62-67.
  J.R. Lindahl, N.E. Fisher, D.J. Cooper, R.K. Rosen, and W.B. Britton, “The Varieties of Contemplative Experience: A Mixed-methods Study of Meditation-related Challenges in Western Buddhists,” PLoS ONE 12, no. 5 (2017): 1.
 Lindahl et al., “The Varieties of Contemplative Experience,” 3-4.
 Lindahl et al., “The Varieties of Contemplative Experience,” 1.
 E. Greene, “Healing Sickness Caused by Meditation: ‘The Enveloping Butter Contemplation’ from the Secret Essential Methods for Curing Meditation Sickness,” in Buddhism and Medicine: An Anthology of Premodern Sources, ed. C.P. Salguero (New York, NY: Columbia University Press, 2017), 373.
 Bhikku Nanamoli, Visuddhimagga: The Path of Purification (Kandy, Sri Lanka: Buddhist Publication Society, 2011), 666-681. Accessed 10 April 2018: https://www.urbandharma.org/pdf1/PathofPurification2011.pdf.
 N.R.M. Ehara, S. Thera and K. Thera, Vimuttimagga: The Path of Freedom (Kandy, Sri Lanka: Buddhist Publication Society, 1961), 299-301. Accessed 10 April 2018: http://urbandharma.org/pdf1/Path_of_Freedom_Vimuttimagga.pdf.
 N.M. Thera, A Manual of Abhidhamma (Kuala Lumpur, Malaysia: Buddhist Missionary Society, 1987), 478. Accessed 10 April 2018: http://www.buddhanet.net/pdf_file/abhidhamma.pdf.
 Thera, A Manual of Abhidhamma, 478. Also, the Vimuttimagga, 299-301.
 L. VanderKooi, “Buddhist Teachers’ Experience with Extreme Mental States in Western Meditators,” The Journal of Transpersonal Psychology 29, no. 1 (1997): 32-33.
 Bhikshu Dharmamitra, The Essentials of Buddhist Meditation: The Essentials for Practicing Calming-and-Insight & Dhyāna meditation—The Classic Śamathā-Vipaśyanā Meditation Manual by the Great Tiantai Meditation Master & Exegete Śramaṇa Zhiyi (Seattle, WA: Kalavinka Press, 2009), 169-188.
 Bhikshu Dharmamitra, The Essentials of Buddhist Meditation, 169.
 P. Kapleau, The Three Pillars of Zen: Teaching, Practice, and Enlightenment (New York, NY: Anchor Books, 2000), 45.
 M.H. Kohn, The Shambhala Dictionary of Buddhism and Zen (Boston, MA: Shambhala, 1991).
 Also, Kapleau writes: “While disciplining himself in meditation the Yogin is liable to be visited by all kinds of evil beings whereby he is constantly assailed by hallucinations of various natures. These are all due to highly-accentuated nervous derangements, and the Yogin is advised to guard himself against them.” Kapleau, The Three Pillars, 45.
 L.W. Nelson, “Chan (Zen) Sickness and the Master’s Role in its Diagnosis, Treatment, and Prevention,” Unpublished PhD dissertation. (California Institute of Integral Studies, 2012): 80-90.
 J.R. Lindahl, N.E. Fisher, D.J. Cooper, R.K. Rosen, and W.B. Britton, “The Varieties of Contemplative Experience: A Mixed-methods Study of Meditation-related Challenges in Western Buddhists,” PLoS ONE 12, no. 5 (2017): 2.
 In Tibetan medicine, lung (or rlung) is sometimes literally translated as ‘wind’ or ‘wind illness,’ and unbalanced or disordered flows of lung are a key way in which psychiatric disorders are explained. For a detailed discussion see M. Epstein and L. Rapgay, “Mind, Disease, and Health in Tibetan Medicine” in Eastern and Western Approaches to Healing: Ancient Wisdom and Modern Knowledge, eds. A. A. Sheikh and K. S. Sheikh (New York, NY: Wiley, 1989), 124-145.
 J. Paine, Re-Enchantment: Tibetan Buddhism Comes to the West (New York, NY: Norton, 2004), 128.
 A. Cayton (ed.), Balanced Mind, Balanced Body: Anecdotes and Advice from Tibetan Buddhist Practitioners on Wind Disease (FPMT, 2016), 45.
 Cayton, Balanced Mind, 6; 17; 34; 41.
 Cayton, Balanced Mind, 5.
 Cayton, Balanced Mind, 48.
 B. Greyson, “The Physio-kundalini Syndrome and Mental Illness,” The Journal of Transpersonal Psychology 25, no. 1 (1993): 43-58.
 L. Sannella “Kundalini: Classical and Clinical.” In Spiritual Emergency: When Personal Transformation Becomes a Crisis, eds. S. Grof and C. Grof (New York and Los Angeles: Tarcher, 1989), 99-108.
 Greyson, “The Physio-kundalini.”
 G. Krishna, The Awakening of Kundalini (Ontario: Institute for Consciousness Research, 2001): 96-97.
Also, in The Healing Gods, Gunther Brown cites examples of kundalini problems related to hatha yoga and pranayama: “Although many instructors tout yoga’s safety, some yoga proponents warn of physical, psychological, and spiritual risks. Swami Swatmarama, of Yoga Vidya Gurukul University, cautions that performing pranayama in hatha yoga awakens kundalini energy rapidly: “But if one is not prepared to take on this high level energy awakening then this may have negative effects on mind and body.” Swami Narayanananda is more specific about what negative effects might entail: “if a person does not know how to check the currents and to bring down the partly risen kundalini shakti to safer centers, one suffers terribly and it may ruin the whole life of a person or lead one to insanity.” C. Gunther Brown, The Healing Gods: Complementary and Alternative Medicine in Christian America (New York, NY: Oxford University Press, 2013), 133.
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