Using Ketamine to Induce the Near-Death Experience

Mechanism of Action and Therapeutic Potential

About the Author

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Abstract

The near-death experience (NDE) is a phenomenon of wide general interest. Despite its association with sensationalist media reports, populist books of doubtful scientific value, and a series of dubious Hollywood films, the NDE is still of considerable importance to medicine, neuroscience, neurology, psychiatry, psychology and, more controversially, philosophy and theology (Stevenson and Greyson, 1979; Greyson and Stevenson, 1980; Ring, 1980; Sabom, 1982; Jansen, 1989a,b, 1990b, 1995, 1996). Philosophical and theological issues are beyond the scope of the present discussion, which is based within the scientific paradigm and is thus best assessed from within this paradigm.

Recent advances in neuroscience are bringing us closer to a brain-based understanding of the NDE as an altered state of consciousness. This discussion does not address the issue of whether there is life after death, but does argue that NDE's are not evidence for life after death. This would be appear to be self-evident on logical grounds: death is defined as the final, irreversible end. The Oxford English Dictionary (Sykes, 1982) defines death as the 'final cessation of vital functions'.According to this definition, 'Returnees' did not die - although their minds, brains and bodies may have been in a highly unusual state for a period of time. If these definitions are not accepted, then we need a new terminology to describe these states.

There is now evidence from thousands of studies relating brain events to alterations in mental state that 'mind' results from neuronal activity. These studies range from observing the results of directly stimulating the brain with electrodes, for example the pioneering work of the neurosurgeon Wilder Penfield, to the most recent studies using magnetic resonance imaging to observe brain activity, for example to demonstrate activity in the temporal lobe while schizophrenics are experiencing auditory hallucinations (McGuire et al., 1995). The dramatic effects on the mind which result from the action of hallucinogenic drugs in the brain, effects which can include profound religous experiences, provide further evidence for the dependance of mind upon neurochemical and neuroelectrical events (Grinspoon and Bakalar, 1981). However, the dimension in which mind itself exists remains a mystery.

Within a scientific paradigm, it is not possible that "the spirit rises out of the body leaving the brain behind, but somehow still incorporating neuronal functions such as sight, hearing, and proprioception" (Morse, 1989). To believe that this is possible, we must leave the realm of science and adopt a wholly different paradigm.

The Near-Death Experience: Typical Features

The typical features of a 'classic' NDE include a sense that what is experienced is 'real' and that one is truly dead, ineffability (i.e. a sense that what is experienced cannot be described using language, 'beyond words'), timelessness, analgesia, apparent clarity of thought and feelings of calm and peace, although some NDE's have been disturbing and frightening. There may be a perception of separation from the body (out-of-body experiences). Common hallucinations include landscapes, people including partners, parents, teachers and friends (who may be alive at the time), and religous and mythical figures including angels and a representation of 'God' as light. Transcendant mystical states are common. Memories frequently emerge into consciousness, although the organisation of these into a 'life review' is a relatively rare phenomenon. Hearing noises during the initial part of the NDE has been described - the significance of this feature will be discussed later (Noyes and Kletti, 1976a; Morse et al., 1985; Osis and Haraldsson, 1977; Greyson and Stevenson, 1980; Ring, 1980; Sabom, 1982; Greyson, 1983).

Ring (1980) classified NDE's on a 5 stage continuum:
1. feelings of peace and contentment;
2. a sense of detachment from the body;
3. entering a transitional world of darkness (rapid movements through tunnels: 'the tunnel experience');
4. emerging into bright light; and
5. 'entering the light'.

60% experienced stage 1, but only 10% attained stage 5 (Ring, 1980). As might be predicted in a mental state with a neurobiological origin, mundane accounts with less symbolic meaning also occur, e.g. children who may 'see' their schoolfellows rather than God and angels (Morse, 1985).

The intravenous administration of 50 - 100 mg of ketamine can reproduce all of the features which have commonly been associated with NDE's. Intramuscular administration also results in NDE's, but events evolve at a slower pace and are longer lasting (Domino et al., 1965; Rumpf ,1969; Collier, 1972; Siegel,1978, 1980,1981; Stafford, 1977; Lilly, 1978; Grinspoon and Bakalar, 1981; White, 1982; Ghoniem et al., 1985; Sputz, 1989; Jansen, 1989a,b, 1990b, 1993, 1995, 1996).

Mounting evidence suggests that the reproduction/induction of NDE's by ketamine is not simply an interesting coincidence. Exciting new discoveries include the major binding site for ketamine on brain cells, known as the phencyclidine (PCP) binding site of the NMDA receptor (Thomson et al., 1985), the importance of NMDA receptors in the cerebral cortex, particularly in the temporal and frontal lobes, and the key role of these sites in cognitive processing, memory, and perception. NMDA receptors play an important role in epilepsy, psychoses (Jansen and Faull, 1991), and in producing the cell death which results from a lack of oxygen, a lack of blood, and from epileptic fits (excitotoxicity). This form of brain cell damage can be prevented by administration of ketamine. Other key discoveries include that of chemicals in the brain called 'endopsychosins' which bind to the same site as ketamine, and the role of ions such as magnesium and zinc at this site (Anis et al., 1983; Quirion et al., 1984; Simon et al., 1984; Benveniste et al., 1984; Ben-Ari,1985; Thomson, 1986; Coan and Collingridge, 1987; Collingridge, 1987; Contreras et al., 1987; Cotman and Monohan, 1987; Rothman et al., 1987; Mody et al., 1987; Nowak et al., 1984; Quirion et al., 1987; Westbrook and Mayer, 1987; Sonders et al., 1988; Barnes,1988; Choi,1988; Monaghan et al., 1989; Jansen et al., 1989a,b,c, 1990a,b,c, 1991a,b,c, 1993, 1995, 1996).

Ketamine administered by intravenous injection is capable of reproducing all of the features of the NDE which have been commonly described (Domino et al., 1965; Rumpf, 1969; Collier, 1972; Siegel,1978, 1980, 1981; Stafford, 1977; Lilly, 1978; Grinspoon and Bakalar, 1981; White, 1982; Ghoniem et al., 1985; Sputz, 1989; Jansen, 1989a, b,1990b, 1991c, 1993, 1995, 1996; Kungurtsev, 1991).

Unfortunately, the study in which persons who have had NDE's are given ketamine and asked to compare the two experiences has yet to be carried out, although the psychological effects of ketamine have been well documented in numerous clinical studies by anaesthetists (see Domino, 1992). Information in the area of ketamine and NDE's remains largely anecdotal, and some of these references are necessarily to secondary sources. The present author has experienced several NDE's and has also been administered ketamine as an anesthetic and within experimental paradigms. The NDE's and ketamine experiences were clearly the same type of altered state of consciousness. Ketamine repeatedly produced effects which were like the NDE's described by Moody (1975), Noyes and Kletti (1976a), Greyson and Stevenson (1980), Ring (1980), Sabom (1982) and Morse et al., (1985). Ketamine reproduced travel through a tunnel (sometimes described as 'the plumbing of the world', or in mundane terms such as 'like being on a subway train'), emergence into the light, and a 'telepathic' exchange with an entity which could be described as 'God'. Neither the NDE's nor the ketamine experiences bore any resemblance to the effects of psychedelic drugs such as dimethyltryptamine (DMT; also administered to the author in experimental paradigms) and lysergic acid diethylamide (LSD).

Ketamine: Typical Features

The altered state of consciousness resulting from ketamine administration is very different from that produced by psychedelic drugs such as LSD and DMT (Grinspoon and Bakalar, 1981).