Research has shown that altered states of consciousness induced by yoga and meditation are common among the general population.

Practices such as yoga, mindfulness, meditation and breathwork are growing in popularity due to their potential to improve health and well-being. While the effects of these practices are mostly positive and sometimes transformative, they are known to involve shifts in consciousness that can sometimes be difficult.

A new study from a team that includes researchers from Massachusetts General Hospital finds that altered states of consciousness associated with meditation practices are far more common than expected.

While many reported positive outcomes from these experiences, sometimes even considered transformative, for a significant minority the experience was negative. The results are published in the journal Mindfulness.

“Given the growing number of people engaging in mindfulness, meditation, and other contemplative and mind-body practices, we suspected that altered states and their effects might be common among the general population. We conducted a series of international surveys to investigate and found that such experiences are indeed widespread,” said lead author Matthew D. Satchett, PhD, director of the Meditation Research Program at Massachusetts General Hospital and associate professor of psychiatry at Harvard Medical School.

“Altered states of consciousness almost always have a positive effect on well-being and can sometimes be transformative,” Satchett added, “although there have been some reports of negative effects on well-being and a small number of individuals have reported significant distress.”

For the study, a panel of experts in psychiatry, neuroscience, meditation, and research design developed a questionnaire about experiences of altered states of consciousness.

Of 3,135 US and UK adults who responded to an online survey, 45% reported experiencing a non-drug-induced altered state of consciousness at least once in their lifetime.

This is far more than would be expected from the estimated 5% (US) to 15% (UK) of the population who practice mindfulness.

Experiences included derealization (a feeling of being detached from the environment), a sense of oneness (a sense of unity or “oneness”), ecstatic excitement, vivid perceptions, changes in perceived size, body heat or electricity, out-of-body experiences, and perceptions of non-physical light.

Respondents reported a mixture of positive and negative well-being after the degenerative condition, with 13% reporting moderate to severe distress and 1.1% reporting life-threatening distress. Of those who experienced distress, 63% did not seek help.

“Our research shows that altered states of consciousness are not extremely rare or unusual, but rather a common variation of normal human experience,” said Satchett, “but we find that people who experience the negative outcomes associated with these altered states often do not seek help, and clinicians are ill-prepared to recognise or support these types of experiences. A certain number of people have difficulty integrating their experiences of altered states into their existing concept of self and reality, which makes this a considered public health issue.”

Satchett noted that further research is needed to identify the individual characteristics associated with experiencing altered states of consciousness and the potential distress associated with these states, and he also stressed the importance of translating this research into patient care.

“Meditation and other practices should not be dismissed as inherently dangerous, but rather we need to better understand meditators and help them realize the full potential of these practices,” he said. “As with psychotherapy, pharmacology, and other therapeutic tools, it is important to learn how to best implement and support those who engage with these powerful practices.”

He added: “Ancient meditation manuals from wisdom traditions may help us classify and understand altered states of consciousness. They may provide guidance on how to better manage altered states when they are difficult. Clearly more research is needed to further explore and understand this possibility.”

“Clinical curricula on altered states of consciousness need to be developed to better support clinicians caring for patients experiencing the distress associated with these experiences,” Satchett added.

“And those who teach meditation practices should make sure participants are aware of the potential risks,” he said. “These types of safeguards combined will ensure that these very promising and powerful practices are taught and experienced safely.”