Near Death Experiences
Key Questions About NDEs for Further Study
Near Death Experiences Series, Article 10 (Reviewed by the Editorial Board)
Although the NDE phenomenon has received a lot of media attention since the publication of Moody’s “Life after life” in the ‘70s, a simple search for “Near Death Experience (s)” in Pubmed (1) only provides a hundred or so returns, not very encouraging for such a popular subject. Any other scientific subject would probably yield hundreds or even thousands of entries.
A closer look and search through the medical literature also shows that there are only a handful of scientific studies and most of the publications are either anecdotal case reports, or speculative physiological theories which are not underpinned by the wide phenomenology of the NDE and which quote references to mechanisms which are not possible.
It has been claimed, for example, that opioids are the basis of the NDE as they can produce relaxed and pleasant mental states. It is possible to produce very high levels of brain opiates by injecting morphine. Yet there is not one single report of mental states like the NDE occurring in these situations.
An NDE is a common mental state that can be entered by many different routes; when the brain is not functioning, as in cardiac arrest, when close to death as in accidents, serious illness etc, when extremely frightened, or when it is associated with a transient mystical experience, which can occur when you are relaxed and without any evidence of bran pathology. Looking at this list will tell you that there is very unlikely to be a single causative mechanism.
It is also important that proper prospective studies are carried out, for example on people who have cardiac arrests, as approximately 10% of these people will have a near death experience (2). If it could be shown that the NDE occurred during the arrest at the time when the brain is dysfunctional, then one would need to look for other theories relating to its causation. It might, for example, point to the possibility of mind and brain being separate.
In order to study the phenomenon objectively it is important to examine a number of key questions:
A. Is a near death experience a modern phenomenon or did it also occur in ancient times?
There have been references to the near death experience phenomena in the art and literature of many different cultures since ancient times. Many cultures have the story that when we die we go to some other form of reality. In these earlier accounts we can recognize the same features as we see today. (3) (4)
It is important for us to know whether the characteristics of the near death experience have changed across time, or are different in different cultures. If they have changed or are different, this would indicate that they are a cultural phenomenon rather than a fundamental part of human experience and it would have little scientific interest to study them.
It has been argued, for example, that because of its long history the NDE is well known in our Western society and has become a copy-cat phenomenon – people experience what they expect to experience. However, in a sample of over 500 NDEs recorded in 1987, before knowledge of the NDE in our culture had become so widespread, 98% claimed that at the time they had their NDE they had known nothing about it. It would not be possible to get such a sample again.
B. How common is an NDE and is it associated with a particular personality type, culture, religious belief or age?
If these experiences are simply a consequence of age, or a particular personality type, or are the product of a strong religious or cultural belief, then they are of little scientific interest. Although the content of an NDE is often influenced to some extent by a strong cultural or religious belief, there is no evidence that the experience itself is due simply to belief or expectation.
C. How can we classify an NDE, as opposed to other mental states and experiences?
Visions, or hallucinations, can occur in many different mental states, for example, schizophrenia, bipolar illness, intensive care psychoses, drug-induced psychoses, to mention just a few. However, a near death experience has a common characteristic which makes it quite different from these other mental states which are much more variable and often confused. An NDE is a clear and lucid experience instead. Many other mental states may contain some elements common to the NDE but the overall picture is always different.
D. How could the occurrence of a near death experience be explained scientifically?
Examining the medical literature, it becomes clear that these questions are in fact those that have occupied researchers in the 1970s, 1980s and 1990s and some of the answers are available. In fact, (point A) and B) here above are discussed in other articles (2, 3, 4, 5, 6). Now, in upcoming articles we will examine different classification systems for a near death experience (point C) and also look at different theories of causation for this phenomenon (point D).
......... If you want to know more, visit the near death experiences section of our web site (7)
(1) First released in January 1966, PubMed is a free database consisting of over 20 million references, abstracts and sometimes full free articles on life sciences and biomedical topics maintained by the United States National Library of Medicine (NLM) at the National Institutes of Health.