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Overview
Hypoxia
Endorphins
Seizures
Hallucinations
Psychological Factors and NDEs
Expectation
G-LOC: Gravity Induced Loss of Consciousness
REM-Intrusion
Drugs/Medicines
Electrical Brain Stimulation
Magnetic Brain Stimulation
OBE Observations in NDEs are “Lucky Guesses”
NDEs are False Memories from Entering into or Recovering from Unconsciousness
NDEs Under General Anesthesia are from Too Little Anesthesia
Summary





Overview

Skeptics continue to argue that near-death experiences are hallucinatory and/or unreal memories. Out of respect for people’s ability to generally understand reality, if skeptics want to claim that NDEs are not real, then it is the responsibility of the skeptics to present convincing evidence that NDEs are not real. However, skeptics are unable to adequately explain any of the major lines of evidence for the reality of NDE. Skeptics have proposed more than twenty different and widely varying “explanations” of NDEs. If skeptics as a group accepted any of these “explanations” as plausible, then there would not be such a large number of varied skeptical arguments purporting to show that NDEs are unreal.

In considering any skeptical argument, it is crucial to determine if the skeptical “explanation” adequately explains all of the lines of evidence for the reality of NDE. The most significant skeptical arguments are compiled and refuted in this article. This is a work in progress. Out of fairness to the NDE skeptics, if any skeptic wants to respond to anything written in this article, I will gladly post their comments along with my response. In seeking to understand the truth about NDEs, it is vital to carefully consider the skeptical arguments.

Hypoxia

During a cardiac arrest, blood immediately stops flowing to the brain. Blood flow to the brain normally carries oxygen, which the brain requires for normal functioning. The medical term hypoxia refers to reduced levels of oxygen in the brain and other bodily tissues. Reduced or absent blood flow is also associated with increased levels of carbon dioxide in the blood, which is called hypercapnia. Some skeptics have suggested that hypoxia and/or hypercapnia may account for NDEs.

The evidence contradicts this skeptical suggestion. It is a well established medical fact that as patients become increasingly hypoxic, there is a progression toward disorientation, confusion, and finally unconsciousness. This lack of mental clarity which is consistently associated with hypoxia is virtually never seen in NDEs. NDEs are generally organized, lucid, and usually involve supernormal levels of consciousness and alertness.

One prior NDE researcher was able measure blood levels of both oxygen and carbon dioxide during NDEs, and found no effect of either hypoxia or hypercapnia on the experience (Sabom, 1982, Recollections of Death: A Medical Investigation). The presence of hypoxia and the expected diminished mental status at the time of a life-threatening event is actually a strong argument for the reality of NDE.

Endorphins

Endorphins are chemicals naturally produced in the brain in response to major pain or stress. They quickly act to reduce the sensation of pain, and may produce feelings of peace and well-being. NDEs commonly include peaceful feelings and almost always have an absence of pain. Skeptics have asked if endorphins might account for the absence of pain and positive feelings during NDEs.

Of course endorphins could not account for the great majority of other elements typically observed during NDE. Even more importantly, when endorphins are released in the brain, they produce a reduction in the sensation of pain that generally lasts for hours. The period of unconsciousness in NDEs often lasts seconds to minutes. When NDErs return to their physical body at the end of the NDE, they typically describe immediate and substantial pain as result of the life-threatening event. The absence of pain occurring during NDE almost never continues for a prolonged period of time after the end of the NDE. Endorphins appear to have no causal role in the occurrence of any NDE element.

Endorphins are natural opiate chemicals. They mimic the effect of morphine (and other narcotics). Morphine, and other opiates are commonly used as analgesics. It is significant that virtually no NDEr has described narcotics as reproducing any element of the NDE. Very high levels of endorphins are found following a grand mal seizure. Yet virtually nobody after a grand-mal seizure describes peaceful/euphoric sensation that would be expected with endorphins. It is not logical to assume endorphins only produce peaceful/positive emotions in unconscious patients. NDEs, and a complete absence of pain, often start instantly when an accident occurs with sudden unconsciousness. This immediate lack of pain occurring immediately after the trauma is almost certainly too sudden in onset to be accounted for by endorphins. One study involved injecting endorphins. After injection, the sensation of touch and sharp stick remained intact, which is not seen during NDEs where there is generally an absence on any physical sensation. Injected endorphins also caused substantial sleepiness in the subjects, and such sleepiness is almost never observed in NDEs. In people who nearly die, but do not have a NDE, feelings of pleasantness or ecstasy are almost never observed, but would be have been expected to occur if endorphins played a significant role at the time of life-threatening events.

Seizures

A seizure is an abnormal electrical discharge in the brain due to a variety of causes. Depending on how severe the seizure is, unconsciousness may or may not occur.

Skeptics have wondered if seizures, especially those occurring in the temporal lobes, might account for some elements of NDEs. The temporal lobes are on the right and left side of the brain. There have been occasional reports of temporal lobe seizures being associated with feelings of ecstasy and OBE observations that are often unreal. There are only a few reported experiences associated with temporal lobe seizures with superficial similarity with typical NDEs. Temporal lobe epilepsy experiences are more likely to be fragmentary, involve a sense of fear, and may have bizarre unrealistic imagery that contrasts with the striking reality of NDE imagery (See: Journal of Near-Death Studies 26:2, 2007, p. 132).

One Neurologist who has experience with hundreds of patients with temporal lobe seizures stated “In spite of having seen hundreds of patients with temporal lobe seizures during three decades of professional life, I have never come across that symptomatology (of NDEs) as part of a seizure” (See: Comments on “A neurological model for near-death experiences.” Journal of Near-Death Studies, 7, 255-259, p. 256.) Many NDEs have been reported on NDERF that occurred in association with seizures that were so severe that they resulted in a life-threatening event. In reviewing these accounts, it appears doubtful that these NDEs were caused solely by seizures, but much more likely that the NDE was caused by the cessation of breathing and often heart function that can happen during especially severe seizures.

The best available evidence indicates that seizures, including temporal lobe seizures, do not cause NDEs or any element of NDEs.

Hallucinations

Hallucinations are perceptions in the conscious and awake state that have the sense of reality, but in fact are not real. The “acid test” for the possibility that NDEs are hallucinations is the degree of reality of NDE content. As the NDERF studies have shown, NDEs have nearly uniformly realistic observations in the OBE state. Life reviews during NDEs are also highly realistic and may include real events in their lives, even if the NDErs had long forgotten the events. NDEs usually occur with a higher degree of consciousness and alertness than everyday life. None of these observations are consistent with NDEs being hallucinations.

Leading NDE researcher Dr. Bruce Greyson put it succinctly in pointing out that “Every large study of NDE reported in mainstream medical journals has concluded NDEs cannot be considered hallucinations. This unanimity of scientists is very unusual. NDEs are NOT hallucinations or psychosis.” Every shred of evidence indicates NDEs are not hallucinations.

Psychological Factors and NDEs

Multiple prior studies evaluated the mental health of NDErs. The consensus of these studies was that the mental health of NDErs is indistinguishable from non-NDErs (See: Greyson, B. 2000b. Near-death experiences. In E. Cardeña, S. J. Lynn, and S. Krippner, S. (Eds), Varieties of anomalous experience: Examining the scientific evidence (315-352). Washington, DC: American Psychological Association.) Put another way, NDErs are no more likely to have mental illness than non-NDErs. Skeptics continue to speculate about the possibility that psychological factors other than mental illnesses might contribute to the predisposition to have a NDE, or affect the NDE content.

Prior NDE researchers have studied the possibility of that NDErs may differ from non-NDErs with regards to a number of pathologic and non-pathologic psychological factors. Factors studied have included depersonalization, absorption, fantasy proneness, and others.

I co-authored a book chapter that included a detailed review of this topic. (See: Holden J, Long J, MacLurg J. Characteristics of Western Near-Death Experiencers. In: Holden J, Greyson B, James D, eds. The Handbook of Near-Death Experiences: Thirty Years of Investigation. Westport CT: Praeger Publishers; 2009.) We found that most previously studied psychological factors did not affect either the probability of a NDE occurring during a life-threatening event, or the NDE content. There were a few psychological factors that might contribute to NDEs, but further research would be necessary to draw any definitive conclusions.

A major reason for this degree of uncertainty regarding NDEs and psychological factors is that all major prior studies of this topic have been retrospective. Thus, these studies cannot determine if any psychological characteristic of NDErs that appears different than non-NDErs is due to an aftereffect of the NDE, due to the NDErs in the sample not being representative of all NDErs, or if the apparent psychological differences truly existed in the NDErs prior to their NDE. This is especially an issue given that NDErs often share their NDEs many years after their NDE, a median of 15 years later in the NDERF study. Putting this another way, NDErs have the experience of nearly dying, have a typically profound NDE, then commonly have dramatic and lasting changes in their values, beliefs, and relationships in the years following the NDE. It is easy to see how the experience of a NDE and its aftereffects could affect the NDEr’s psychology.

Thus no retrospective study of NDEs and psychological factors can definitively conclude that any psychological factor causes NDEs or modifies the content of the experience. Prospective study of psychological factors and NDEs will be necessary before any definitive conclusions can be made.

Expectation

Some skeptics have suggested that NDEs occur as a way to protect oneself from a life-threatening event. Perhaps this is a psychological defensive reaction. Perhaps this is a human reaction that is analogous to animals that ‘play dead’ in response to a predatory attack that they cannot escape.

The best response to this is that large numbers of NDEs have been reported where the life-threatening event was unexpected, with immediate loss of consciousness. There would have been no time to develop a psychological response. This is also seen in the van Lommel prospective study (See: van Lommel P, van Wees R, Meyers V, Elfferich I. Near-Death Experience in Survivors of Cardiac Arrest: A Prospective Study in the Netherlands. Lancet. 2001;358:2039–2045.) where some cardiac arrest patients had no symptoms preceding the heart attack, and suddenly lost consciousness at the time of their cardiac arrest. The presence or absence of fear prior to the cardiac arrest was not associated with whether a NDE occurred or not.

If NDE content was modified by prior awareness of NDEs, it would be expected that there would be a difference in NDEs occurring before 1975, before NDEs became widely known with the publication of Dr. Moody’s book “Life After Life”, and after 1975. Several studies found no difference in the content of NDEs that happened before or after 1975 (See: Long, J. P., & Long, J. A. (2003) A Comparison of Near-Death Experiences Occurring Before and After 1975: Results From an Internet Survey. Journal of Near-Death Studies. 21-32., Athappilly G., Greyson B., Stevenson I. (2006) Do prevailing societal models influence reports of near-death experiences? The Journal of Nervous and Mental Disease. 194:218-222.)

NDErs virtually always encounter only deceased beings, mainly relatives, and only very uncommonly those alive at the time of the NDE. These deceased beings may have died years or even decades prior to the NDE. They are virtually always the picture of health, even if the NDEr’s last remembrance of them was very debilitated shortly before their death. There are many reports of NDErs meeting deceased relatives that they did not recognize during their NDE, and only recognized them when they saw pictures of them after the NDE. There are also reports of NDErs encountering those they did know were dead at the time of their NDE, but they actually were. This pattern of deceased beings encountered by NDErs almost single-handedly refutes the expectation argument.

NDErs commonly express a sense of surprise during their NDEs. Examples of this include surprise that a bright light does not hurt their eyes, and surprise that a body below them is themselves. If NDEs were caused by what the NDErs expected, it would be expected that there would be few or no NDEs with a sense of surprise during the experience.

G-LOC: Gravity Induced Loss of Consciousness

Modern military fighter jets are able to accelerate and turn at incredible speeds. Maneuvering jets at high speed may greatly increase the gravitational forces on the pilots. These increased gravitational forces can be severe enough that the pilot becomes unconscious. This gravity induced loss of consciousness has been abbreviated “G-LOC”. The United States Air Force was very concerned about G-LOC, as this could cause a crash with loss of both the life of the pilot and loss of the fighter jet.

The Air Force studied G-LOC by creating a giant centrifuge that would simulate G-LOC. Nearly 1000 episodes of G-LOC were studied in this manner. Some skeptics have suggested that the pilots’ experiences while unconscious simulated some aspects of NDE, including OBE, pleasant emotions, and visions. Some subjects reported ‘dreamlets’. These dreamlets were brief dream-like experiences that included such content as a feeling of being in an enclosed space, confusion, anxiety, being in a colorful open area, and encountering living people, but never deceased people. Dreamlets exhibited characteristics typical of dreams including illogical content and difficulty in recalling the experience. Many of these preceding characteristics common found in dreamlets occur only rarely during NDEs.

The physician in charge of the Air Force G-LOC experiments concluded that there are characteristics unique to NDE that did not occur in the G-LOC experiments (See: Whinnery, 1997, Journal of Near-Death Studies 15(4), p. 231-238).

The few G-LOC examples described in the literature are subjectively quite different from NDE. One researcher, Dr. Penny Sartori, references a person who had a G-LOC experience and NDE, and found the two experiences were not at all similar.

REM-Intrusion

There has been a suggestion that REM-intrusion might account for some elements of NDE. REM-intrusion is a normal part of sleep that commonly features vividness, emotional intensity, and bizarre imagery. REM stands for rapid eye movement. REM-intrusion may be associated with a sense of paralysis, commonly called “sleep paralysis”, though breathing actually continues. REM-intrusion experiences usually last from seconds to minutes.

The possible association of REM-intrusion and NDE was first described in a study by Dr. Kevin Nelson in 2006 in the medical journal Neurology, a major medical journal. Almost immediately there was intense media interest. Some media presentations overstated the findings of Dr. Nelson’s study and implied that NDE was finally “explained” by REM-intrusion.

I co-authored a response to Dr. Nelson with the great assistance of Dr. Janice Holden. (See: Does the Arousal System Contribute to Near Death Experience?: A Summary and Response. (2007). Jeffrey Long, M.D. & Jan Holden, Ed. D. Journal of Near-Death Studies, 25(3), 135-169.) Any interested readers are invited to read this article. I, and I believe most others, consider this article to adequately refute the Nelson article’s suggestion that REM intrusion accounts for NDEs.

Drugs/Medicines

Only a very small percentage of NDEs are associated with the concomitant use of medicines or drugs that could be expected to significantly affect the brain. Of all drugs that act on the brain, the one most commonly suggested as possibly mimicking some aspects of NDE is ketamine and pharmacologically related substances. A number of ketamine experiences have been described by those using ketamine illicitly. It is appropriate to be cautious about the credibility of any experiences described by those using drugs illegally. With this important cautionary warning in mind, some ketamine users have described experiences including a tunnel, light, or communing with God (((Ref IM bottom p. 380 – top 381))).

A review of typical ketamine experiences from credible sources establishes that ketamine experiences are not like NDEs. Ketamine experiences are much more likely to be bizarre, obviously unreal, and often frightening. Most ketamine users recognize their experienced is illusory, which is not true of virtually all NDErs. Several ketamine experiences have been shared with NDERF. These experiences are consistent with typical ketamine experiences and have nothing significantly in common with typical NDEs. A natural ketamine-like substance has yet to be found in humans.

Recently there has been public interest in DMT (N, N-dimethyltryptamine, a hallucinogenic drug), and its possible relationship with NDE. DMT does not cause NDEs. DMT experiences are substantially different from NDE experiences. You can see this for yourself. Here are first-person sequentially shared DMT experiences (without concomitant use of other substances): https://www.erowid.org. You can compare DMT experiences with sequentially shared first-person NDE experiences: https://www.nderf.org/Archives/NDERF_NDEs.html. You can objectively compare the experiences by reading sequentially shared experiences from both links. Anyone who reads 30 experiences of each type should easily see the substantial difference between DMT experiences and NDEs.

Electrical Brain Stimulation

Electrical brain stimulation may sound like science fiction to many. The brain lacks nerve fibers that allow pain to be felt, so the procedure of electrical brain stimulation is not ordinarily painful. Patients undergoing this procedure are generally awake, though they may be lightly sedated. Electrical brain stimulation remains under active clinical use for a variety of indications. One use of electrical brain stimulation is a procedure called “brain mapping” which helps localize a diseased area of the brain that is causing seizures.

Over the years it has been interesting to see ‘urban myths’ about NDE come, and then hopefully go away. One myth that was widely believed in the past involved the results of electrical brain stimulation performed decades ago by Neurosurgeon Dr. Wilder Penfield. This myth was that electrical brain stimulation, particularly stimulation of the brain’s right temporal lobe, produced experiences “strikingly similar” to NDEs.

A closer look at Dr. Penfield’s published results of electrical brain stimulation effectively refutes the myth that they resemble NDEs. Most experiences reported by Dr. Penfield were obviously not typical NDE experiences, such as hearing bits of singing or music, bizarre imagery, and fearful emotions.

Modern reports of electrical brain stimulation find that it produces experiences similar to those described by Dr. Penfield; experiences quite unlike NDEs. Several recent case reports have suggested that out-of-body experiences (OBEs) may be produced by electrical brain stimulation. The first major report of purported OBE from electrical brain stimulation was published in 2002 in Nature (See: Blanke, O., Ortigue, S., Landis, T., & Seeck, M. (2002). Stimulating illusory own-body perceptions: The part of the brain that can induce out-of-body experiences has been located. Nature, 419, 269-270.) There was intense media interest with occasional overstatement of the Blanke et al. study findings, with some media accounts suggesting the source of OBEs in the brain had been found. I co-authored a response to this article. This article was published in the Journal of Near-Death Studies (See: Out-of-Body Experiences: All in the Brain? Jan Holden, Ed.D., Jeffrey Long, M.D., Jason MacLurg, M.D. (2006). Journal of Near-Death Studies, 25(2), 99-107.) and the full text of this article is available on the Internet (Ref: http://www.iands.org/research/important_studies/out-of-body_experiences_all_in_the_brain.html. This article concluded:

“In summary, the Nature authors did not produce an OBE in their patient that was typical of spontaneous OBEs. Although they reconfirmed a possible neuroelectrical mechanism involved in at least some OBEs, they did not explain the cause of the spontaneous phenomenon. Finally, although they showed that some OBEs may involve illusory perceptions, they did not resolve the question of whether at least some spontaneous OBEs involve accurate, “real” perceptions.”

Magnetic Brain Stimulation

A special helmet was developed by Dr. Michael Persinger which allowed focused weak magnetic stimulation of the brain. At one time, Dr. Persinger claimed this technique produced all major components in NDE. This created enormous media interest. But is this really so? Prominent NDE researcher Dr. Bruce Greyson flatly states “However, we have been unable to find phenomenological descriptions of his subjects adequate to support this claim, and the brief descriptions that he does provide in fact bear little resemblance to NDEs.

Another prominent scientific group set out to investigate Dr. Persinger’s claims. They tested magnetic brain stimulation using the scientifically sound method of a “double-blind study.” In this type of study, neither the research investigator nor subject knows when the magnetic stimulation is being given. This investigation failed to reproduce Dr. Persinger’s findings, and concluded that “suggestibility may account for previously (Persinger’s) reported effects.” After this finding was reported, there was an appropriate substantial reduction in media interest in magnetic brain stimulation.

One night I was watching a show on TV where a NDEr I knew was undergoing magnetic brain stimulation in Dr. Persinger’s laboratory. The show left viewers with the impression that the NDEr experienced “something” that “might” resemble a NDE in some ways. I later e-mailed the NDEr and asked in a very open-ended manner about his experience in Persinger’s lab. The NDEr responded bluntly “it failed… Quite disappointing actually.” There is no sound scientific evidence to suggest magnetic brain stimulation consistently reproduces any element of NDE.

OBE Observations in NDEs are “Lucky Guesses”

This skeptic argument is refuted by the consistent accuracy of OBE observations in NDEs found in multiple large studies, including the NDERF studies. These prior studies included hundreds of entirely realistic OBE observations. In addition, many dozens of OBEs during NDEs later verified as accurate by the NDErs themselves or others. Additionally, the vast number of case reports with accurate OBE observations, both previously published and posted on the NDERF website, refute the skeptics. This is further illustrated in over a dozen examples of NDEs with verified OBE observations in supplemental material on the NDERF website (See: Examples of Near-Death Experiences with Verified OBE Observations. https://www.nderf.org/Hub/verifiedOBE.htm.) It is relatively rare for NDERF to receive an NDE account with an OBE observation that was either unrealistic or later verified as not having occurred.

NDEs are False Memories from Entering into or Recovering from Unconsciousness

Another popular skeptical “explanation” of near-death experiences is that NDEs are only false memories occurring as NDErs enter or exit unconsciousness from their life-threatening event. This skeptic argument is largely refuted by the fact that during NDEs the maximal level of consciousness and alertness is generally not before or after unconsciousness. During NDEs, the maximal consciousness and alertness is typically when the body is unconscious. This is illustrated in an NDERF survey question which asks, “At what time during the experience were you at your highest level of consciousness and alertness?” Hundreds of narrative responses to this question have been reviewed, and NDErs typically state that their highest level of consciousness and alertness is not at the beginning or end of their NDE, but somewhere during the NDE or throughout the entire NDE. It is very uncommon for NDErs to state that their highest level of consciousness and alertness was when they were entering into or recovering from unconsciousness. This is further strong evidence that OBEs occur during NDEs, and are not simply false memories.

Near-death experiencers almost always believe that their consciousness separated from their bodies, and their OBE observations were real. With hundreds of accurate OBE observations, we now have substantial evidence from NDEs that consciousness occurs apart from the physical body and are not false memories, but real observations of ongoing earthly events during the NDEs.

NDEs Under General Anesthesia are from Too Little Anesthesia

Near-death experiences can occur under general anesthesia when the heart stops due to a variety of causes. NDEs under general anesthesia are a powerful argument that NDEs are not due to physical brain function. Of course this skeptic argument overlooks NDEs that result from accidental anesthesia overdose. Skeptics also overlook the fact that too little anesthesia, medically termed anesthesia awareness, produces experiences that are totally unlike NDEs. Unlike NDEs, anesthesia awareness experiences are usually unpleasant, painful, and frightening experiences (See: Wilson SL, Vaughan RW, Stephen CR. Awareness, Dreams, and Hallucinations Associated with General Anesthesia. Anesthesia and Analgesia. 1975;54(5):609-616.) Anesthesia awareness more often involves brief and fragmentary memories with hearing described more than vision, which is unlike NDEs. Fortunately, anesthesia awareness is rare, with only about 1 to 3 in 1000 patients experiencing this.

Summary

This article reviewed the major skeptic arguments regarding NDE. Skeptic arguments typically consist largely of unsupported speculation about what might be happening during NDE and what might cause parts of NDE. There is generally a lack of actual evidence to support the skeptical arguments.

The consistent weakness of these skeptic arguments helps explain why there are over 20 different skeptical “explanations” of NDE. These skeptical arguments are so weak that even the skeptics themselves are unable reach consensus regarding one or several arguments that they believe adequately “explains” NDE.

The skeptic’s “last stand” argument is that perhaps some combination of these individual “explanations” for NDE is the answer. There is no consensus by skeptics on what this “combination” of arguments might be. It is unreasonable to believe that any combination of largely speculative explanations of NDE could explain all of what is observed in the consistently lucid and ordered NDEs with its established highly realistic content. No skeptic proposal for the cause of NDEs comes close to explaining the totality of the overwhelming evidence for the reality of NDE presented from scores of NDE researchers.

In confronting the weakness of the skeptic arguments, it is important to point out that I encourage scholarly consideration of all aspects of NDEs, including possible physiological/psychological correlates. There is much about NDE that remains to be discovered, and further scholarly research is strongly encouraged.

It is likely that in the future, skeptics will continue to propose new “explanations” for NDE. If any such future new skeptical explanations of NDE seem remotely reasonable, then they will be addressed in this section of the NDERF website. This will help assure that everyone has the ability to understand the evidence for the reality of NDE, both for, and skeptical arguments against, on an ongoing basis.

I would be delighted to participate in media presentations regarding NDE that explores the evidence both for and against the reality of NDE. I have been on television, radio, and newspapers/magazines numerous times. I consider this one more important way that I can help to share what is credibly known about NDE with the world, and help us all to better understand NDEs.