Many if not all cultures managed to find plant-based hallucinogens in their local environment. This is not surprising, as such plants are not uncommon and generations of testing plants looking for food would have uncovered these obvious effects. Almost uniformly these plants were incorporated into the spiritual traditions of the culture – the psychedelic experiences were interpreted as external (involving the relationship between the individual and the universe) rather than purely internal (affecting the biochemistry of the brain). This is understandable given the pre-scientific knowledge of cultures when making such discoveries.

The spiritual interpretation of psychedelic drugs, however, continues to this day. However, in the mid-20th century psychologists experimented with what they called hallucinogens to determine if they had a therapeutic potential. This experience was generally a negative one, leading to international banning of the recreational use of hallucinogens or psychedelics.

However, the spiritual use continues, and in fact, in an attempt to distance this use from the psychological or recreational use, a new term has been proposes – “entheogen“.

Entheogen is a neologism used to designate psychoactive substances employed in culturally sanctioned visionary experiences in ritual or religious contexts.

The word derives from the Greek which means “to generate god within”. This is a clear expression of the belief that hallucinogens generate a spiritual, rather than physical, experience. However, neuroscientists have a pretty good idea what is going on in the brain with these substances:

Serotonergic hallucinogens and psychotomimetic anesthetics produce overlapping psychotic syndromes associated with a marked activation of the prefrontal cortex (hyperfrontality) and other overlapping changes in temporoparietal, striatal, and thalamic regions, suggesting that both classes of drugs act upon a common final pathway.

There is much more to the neuroanatomical correlates, but this is a basic overview. These drugs cause sensory overload, mood alteration, a breakdown of our reality-testing circuitry, and a dissociation caused by a breakdown in the circuits that make us feel that we occupy our body and are separate from the universe (in some combination).

This is all part of a larger category of phenomena known as altered states of awareness. Our brains actively generate conscious wakefulness, and this is a very energetic state involving many components. Anything that compromises this process can cause altered states of awareness. This occurs normally through dreaming, but can also occur with sleep deprivation, intoxication, highly emotional states, psychological trauma, or altered physiology.

Spiritual practices that attempt to self-generate an altered state of awareness in an attempt to create a “spiritual” experience have explored many methods, beyond simply using drugs. This was a long prelude leading to the main topic of this post – one such method known as holotropic breathwork.

Holotropic breathing was developed and promoted by a new age psychologist, Stanislav Grof, in 1975. It is described as:

HB is a psychotherapeutic procedure involving hyperventilation, a voluntary, prolonged, mindful, and deep overbreathing procedure supported by music and elective bodywork. The HB session is largely nonverbal and without interventions. It concludes with mandala drawing and sharing. A typical HB session lasts for about 1–3 hours, and the client terminates the session voluntarily.

So basically, it’s voluntary hyperventilation. This is simply another way to alter brain chemistry. There is a common misconception that the breathing alters oxygenation of the blood, but this is mostly not true. If you take a deep breath and hold it, you can extract oxygen from the air held in your lungs for minutes without any difficulty. You don’t have to be breathing for this to happen (until the oxygen content of the breath of air gets too low).

Breathing is mainly about regulating CO2 (carbon dioxide). We breathe to blow off CO2, and for this reason CO2 is the main driver of respiration. Our respiratory drive is a feedback loop that maintains our blood CO2 levels within a very narrow range. When you voluntarily hold your breath, the CO2 levels rise, and you gasp for breath at the end due entirely to high CO2 levels (long before oxygen is a problem). When you voluntarily hyperventilate you blow down your CO2.

CO2 is acidic, and so regulating CO2 levels in the blood is also about regulating the pH of the blood. When you hyperventilate you force CO2 down, alkalinizing the blood (called a respiratory alkalosis). This affects the functioning of the nervous system, causing tingling in the mouth and fingers, light-headedness, and dizziness.

So essentially holotropic breathing is a simple method for creating physiological symptoms in conjunction with meditation to enhance the sense of a spiritual experience. This is again interpreted spiritually by believers:

The process itself uses very simple means: it combines accelerated breathing with evocative music in a special set and setting. With the eyes closed and lying on a mat, each person uses their own breath and the music in the room to enter a non-ordinary state of consciousness. This state activates the natural inner healing process of the individual’s psyche, bringing the seeker a particular set of internal experiences. With the inner healing intelligence guiding the process, the quality and content brought forth is unique to each person and for that particular time and place. While recurring themes are common, no two sessions are ever alike.

I was surprised to find actual published studies involving holotropic breathwork. The first is a small open-label case series just seeing what people feel like when they do it. They found increased measures of self-awareness and temperament, but also a transient increase in paranoia.

The second paper, interestingly, is an exploration to see if this spiritual practice can be appropriated as a psychological intervention in the treatment of anxiety and depression (following in the footsteps of psychedelic research beginning in the 1960s).

The third paper seemed the most legitimate to me. First, it dealt with voluntary hyperventilation – stripping that specific element from the broader context of holotropic breathwork. This is a good way to control for variables, and to properly define exactly what an intervention is. The paper mostly proposed a hypothesis – can we use voluntary hyperventilation to induce symptoms common in panic attacks as part of anxiety therapy? This could be a form of exposure therapy – induce panic attacks in patients in a controlled environment and then teach them how to deal with it cognitively without catastrophizing the symptoms. This intervention to holotropic breathwork is what phlebotomy for polycythemia is to bloodletting.

Holotropic breathwork has become the latest fad, and is being promoted as a spiritual and psychological intervention. However, it is nothing new or unique, and is just another way of tweaking brain function in order to produce unusual experiences that can then be interpreted in line with preexisting narratives.


Posted by Steven Novella

Founder and currently Executive Editor of Science-Based Medicine Steven Novella, MD is an academic clinical neurologist at the Yale University School of Medicine. He is also the host and producer of the popular weekly science podcast, The Skeptics’ Guide to the Universe, and the author of the NeuroLogicaBlog, a daily blog that covers news and issues in neuroscience, but also general science, scientific skepticism, philosophy of science, critical thinking, and the intersection of science with the media and society. Dr. Novella also has produced two courses with The Great Courses, and published a book on critical thinking - also called The Skeptics Guide to the Universe.