Near Death Experiences : Proposed Causes
Near Death Experiences Series, Article 16 (Reviewed by the Editorial Board)
The Near Death Experience Phenomenon : Hallucination, Psychological Stress or a Transcendental Event?
There may be several reasons for Near Death Experiences ( NDEs ) but if we wish to examine them we must know the brain state at the time the NDE occurs. Now this can only be done for certain in one set of circumstances and that is when the heart has stopped, during cardiac arrest. We know then that after 11 to 17 seconds the brain flat lines because of a failure of the brainstem functions. The eyes dilate, there is no cough reflex and respiration stops. Now the brain stem also fires up the cortex so that it can work. No brain stem function, no cortex functioning. In fact you are dead. Thus if the NDE occurs at that time and the evidence suggests that it does, then we know that any brain based explanation that is used must be wrong.
Is a Near Death Experience a Transcendental Event? Does it offer a glimpse of the afterlife? That we can’t yet say although those who have the experience are very clear that it does.
Is it just a hallucination induced by altered blood gas levels, low oxygen, high carbon dioxide? This makes little sense as 10% of people with a cardiac arrest will have an NDE but the other 90% who have no NDE, also have very abnormal blood gas levels. So it can’t be abnormal brain pathology as this is the same in the groups who do and do not have it.
Could it be due to a psychological mechanism to cope with the psychological stress of impending death? In the case of the cardiac arrest NDE this could not be true as the loss of consciousness is so fast when the heart stops that there is no time for the person to be afraid. So psychological reasons are ruled out.
Now, although the exact cause of the NDE is not yet understood, and although many of the mechanisms of causation proposed so far fall short of explaining near death experiences, examining the scientific literature, there are currently three broad views proposed to account for their origin. Some researchers have proposed that an NDE :
(A) is a hallucination resulting from brain based chemical disorders and physiological changes, and that cognitive (1) experiences occur just as the brain is shutting down or the brain recovering; some of these disorders and changes include lack of brain oxygen, increased carbon dioxide, the release of endorphins (the body’s own morphine like substance) and a specific type of seizure known as temporal lobe epilepsy, which is lie an electrical storm in the brain. (2) We have already said why this cannot be true as 90% of cases do not have the experience. So we have to look for a different reason.
(B) may be a psychological stress event related to coming close to death, some kind of psychological defense against the threat of death, and that the near death experience occurs just as the brain is shutting down or the brain recovering. In other words, if people thought they were about to die, they would then imagine experiencing events the way they expected them to occur. (2) This also can’t be true because of the speed of the onset of the experience. So a psychological cause for the NDE during cardiac arrest seems to be impossible, as the brain is unable to produce any conscious experiences at that time.
(C) may support a 'spiritual' or transcendental event. This would require us to re-examine our views about mind and brain, because we do not really know how the mind interacts with the brain.
Though the explanation of a transcendent event when the brain is dead does not fit easily into our current science, yet it probably produces the most likely explanation. We do however need more data.
The most favorable scientific arguments have largely centred around the first two concepts because the current prevailing brain/mind model is one where consciousness and mind are the result of brain processes or neurological events. But given that the brain is non functional during cardiac arrest, we will have to look for other explanations.
Acceptance of the occurrence of NDEs
Although at first, some scientists had been skeptical about whether NDEs even occurred, in modern times most researchers have come to accept that they do take place, also because of the high incidence and prevalence (3). In other words it cannot be due to some kind of mass conspiracy or the result of some attention seekers because there are many thousands of cases. Hence, the main area of debate has focused around the possible cause and significance of the NDE phenomena.
In the upcoming articles we will further analyze and discuss different model of causation of near death experiences
….. We hope you have enjoyed this article. If you want to know more, visit the Near Death Experiences section of the web site (4) where you will find many exciting articles on NDEs, their
characteristics, proposed mechanisms of causation, prevalence ...
(1) Cognitive experiences: refer to experiences dealing with cognition, in other words to the mental process of knowing, formulating judgments, reasoning, perceiving and being aware.
(2) Parnia, S. 2013. Erasing Death. Harper One
(3) How Common Is A Near Death Experience ?