Massive Comparison Of Narrative Accounts Finds Ketamine Trips Are Remarkably Similar to Near Death Experiences (NDEs), Supporting The Neurochemical Model Of NDEs

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Similarity in the most frequently used words in accounts of near death experiences (NDE) and ketamine trips, via Martial et al, 2019

By Christian Jarrett

First-hand accounts of what it is like to come close to death often contain the same recurring themes, such as the sense of leaving the body, a review of one’s life, tunnelled vision and a magical sense of reality. Mystics, optimists and people of religious faith interpret this as evidence of an after life. Sceptically minded neuroscientists and psychologists think there may be a more terrestrial neurochemical explanation – that the profound and magical near death experience is caused by the natural release of brain chemicals at or near the end of life.

Supporting this, observers have noted the striking similarities between first-hand accounts of near-death experiences and the psychedelic experiences described by people who have taken mind-altering drugs.

“I had the feeling of floating, still tied to the remains of my heavy body, but floating nonetheless. I rocked and moved, at times as if on a liquid, undulating surface, at other times rising upwards, like a helium-filled flat container.” Excerpt from Amazing First-time Experience in the K-hole, published by Phaeton at the Erowid Experience vaults.

Perhaps, near death, the brain naturally releases the same psychoactive substances as used by drug takers, or substances that act on the same brain receptors as the drugs. It’s also notable that psychedelic drugs have been taken by the shamans of traditional far-flung cultures through history as a way to, as they see it, visit the after world or speak to the dead.

To date, however, much of the evidence comparing near death experiences and psychedelic trips has been anecdotal or it’s been based on questionnaire measures that arguably struggle to capture the complexity of these life-changing experiences. Pursuing this line of enquiry with a new approach, an international team of researchers led by Charlotte Martial at the University Hospital of Liège has conducted a deep lexical analysis, comparing 625 written narrative accounts of near death experiences with more than 15,000 written narrative accounts of experiences taking psychoactive drugs (sourced from the Erowid Experience vaults), including 165 different substances in 10 drug classes.

The analysis, published in Consciousness and Cognition, uncovered remarkable similarities between the psychological effects of certain drugs – most of all ketamine, but also notably the serotonergic psychedelic drugs like LSD.  Indeed, the five most common category terms in the narrative accounts of people who’d taken ketamine were the same as the five most common in the near death experience accounts suggesting “shared phenomenological features associated with an altered state of perception of the self and the environment, and a departure from the everyday contents of conscious mentation”:

“perception (“face“, “vision“, “saw“), emotion (“fear“), consciousness and cognition (“reality“, “moment“, “universe“, “understand“, “consciousness“, “memory“, “explain“, “learn“), the self and others (“own“, “arm“, “self“, “person“, “human“, “everyone“, “others“) and setting (“door“, “floor“, “inside“, “outside“).”

The findings back up the observations of some of the most famous twentieth-century explorers of the psychedelic world – US psychologist Timothy Leary described trips as “experiments in voluntary death” and the British-born writer and philosopher Gerald Heard said of the psychedelic experience, “that’s what death is going to be like. And, oh, what fun it will be!”.

To an extent the results also support neurochemical accounts of near death experience and especially the controversial proposal that such experiences are caused by the natural release of an as-yet-to-be-discovered ketamine-like drug in the brain (adding plausibility to this account, ketamine is known to act on neural receptors that when activated help to prevent cell death and offer protection from lack of oxygen).

As the researchers note wryly, “unlike other human experiences, dying is difficult to study under controlled laboratory conditions by means of repeated measurements” making it a challenge to investigate near-death experiences experimentally. Although the new research lacks laboratory control, on the plus side the lexical comparison Martial’s team conducted is “massive both in terms of the investigated drugs and the number of associated reports”.

The limitations of the current approach, including a reliance on retrospective reports, often decades old, means, as the researchers put it, that they cannot validate nor refute the neurochemical models of near death experiences. “However,” they add, “our results do provide evidence that ketamine, as well as other psychoactive substances, result in a state phenomenologically similar to that of ‘dying’ … This could have important implications for the pharmaceutical induction of near death experience-like states for scientific purposes, as well as for therapeutic uses in the terminally ill as a means to alleviate death anxiety.”

Neurochemical models of near-death experiences: A large-scale study based on the semantic similarity of written reports

Christian Jarrett (@Psych_Writer) is Editor of BPS Research Digest

4 thoughts on “Massive Comparison Of Narrative Accounts Finds Ketamine Trips Are Remarkably Similar to Near Death Experiences (NDEs), Supporting The Neurochemical Model Of NDEs”

  1. So because they use the same words to describe something that they have never seen before its the same ? Six hundred to 15000 of course some of the same words were used. What of cases like Dr Ben Alexander where the brain showed very low activity ? have they tested any one on drugs and recorded low activity and compared stories. What about verified cases of people who told the surgeons and staff what was going on around them in operating theater. Limited research in a complicated sugject is worse than none.

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  2. Graham Stevens is utterly correct, of course. This study sounds a bit forced. (huge understatement) For instance, the language is shifted such as “tunnelled vision” versus a vision that involves a tunnel. The difference is, one of my NDE reporters said he went over to the edge of the tunnel and put his arm through it to see what it was made of. In other words, his vision wasn’t narrowed, as the study description implies, rather, he found himself inside a literal tunnel with a light at the end.

    Not one of my hundreds of respondents ever used a term like a magical sense of reality. They would take strong exception to that. They argue that what they saw was reality itself, that our perceptions filtered through physical channels we have is dream like. But shifting the definition allows the researchers to “capture” (scare quotes intended) pseudo-common elements.

    Stevens also mentions veridical perceptions, such as Pam Reynolds’ famous case. Pim Van Lommel’s study also included that factor such as the account of the false teeth, those are just two instances off the top of my head. That seems like a highly significant difference. Can ketamine users have their eyes taped shut and still accurately describe what others in the room are doing?

    (The case that got Melvin Morse studying pediatric NDEs was the famous Crystal case, a girl who had drowned, eyes taped shut in the ER, and several days later when she was miraculously recovering fully, she described specifics about the ER when Morse was working to save ner. This disturbed Morse deeply since he was a committed materialist but couldn’t see a way she could have known about what he was doing while she was profoundly unconscious. A famous veridical perception like Reynolds’.)

    Van Lommel also pointed out that the EEG goes flat a few seconds after heartbeat ceases. The brain stops all activity when there is no blood flow. That would make the highly active brains of people on ketamine completely unlike the brains at a dead stop in heart attack cases Van Lommel studied.

    I guess what I am saying is this is an attempt by materialists to force non-conforming data into a box of their own make. It is a sad and failed attempt in my opinion, and open minded people will continue to produce research that doesn’t fit their narrow and deluded definition of reality. Other than that, I have no strong opinions.

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  3. I have flat-lined and I watched from the ceiling of the hospital room as 8 dr’s and interns lifted the entire hospital bed I was on, holding me by my ankles to raise my blood pressure and bring me back, I don’t remember leaving my body or coming back, I just remember watching. Since then I have used frankincense oil on the soles of my feet to help sleep, I have epilepsy, can’t take pain meds and have alot of pain, after about a month of usage I started having floating dreams, eventually seeing relatives who had passed on and we’re angry at me for being where they were, I wasn’t supposed to be there, they never talked to me, until one night my mother came and told me I wasn’t allowed to be there until I had taken care of my children, both adults now, but not stable in their own ways. On another occasion I had gone into a spiral and couldn’t stop spinning and another floater/person came up to me and told me only people with epilepsy do that and I told him I had epilepsy and he told me I shouldn’t be doing what I was doing to get there, he then took me back to I guess where I was sleeping and I immediately woke up. I couldn’t stop the dreams even though I stopped using the oil, on another night I dreamed I was in a place with my brother and he was seized by dark spirits and I couldn’t get him out. I called him the next day described the place to him and he knew where it was right down to the truck in the driveway. I made him promise never to go there again. I researched frankincense oil, it is supposed to be used with a carrier oil, apparently full strength it is much different. I mix it now, but with all I’ve experienced, I believe the conscious soul carries on, I’ve seen far too much not to believe, what I’ve divulged here is just the tip of the iceberg.

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