A Review of the non-medical use of Ketamine: Part 1: Use, Users and Consequences
Jansen, K. L. R. (2001) A review of the non-medical use of ketamine: part 1: use, users and consequences. Journal of Psychoactive Drugs (in press)
A Review of the non-medical use of Ketamine: Part 1: Use, Users and Consequences
4. NEAR-DEATH AND NEAR-BIRTH EXPERIENCES
The near-death experience (NDE) is an altered state of being which can be accessed in various ways, including through ketamine which can produce every feature of an NDE (Rogo 1984; Ghoniem et al. 1985; Jansen 1989; 1990a; 1996a,b;1997a; 2000). In 1973, an anaesthetist was given ketamine i.v. in a lung research study: I had no warning. I heard a dull buzzing and then, within seconds, I was unconscious... I was a mind suspended in space... I was not afraid, I was more curious. 'This is death. I am a soul, and I am going to wherever souls go...' (Johnstone 1973)
An NDE does not necessarily mean that the person is physically near death. This is usually not the case, and ketamine does not stop the heart. There may be a belief that awareness left the body and travelled through a tunnel towards light; the conviction that one has died; apparent communion with God; apparently entering other realities; emergence of old memories; a life review; euphoria; fear; ringing/buzzing/ whistling sounds followed by travel at high speed; inability to feel pain; clarity of thought; and visions of landscapes, angels, people, and religious and mythical figures. Rather than paradise, it is also possible to 'emerge' into Hell. The loss of contact with the external reality and the sense of being part of other, more 'fundamental' realities may be overwhelming. The experience can be split into phases. Like the NDE, ketamine can also produce very abrupt 'shifts' in the mind, as if a switch has clicked. Some people who had an NDE during an emergency have described their resuscitation in detail (Sabom 1982). Many surgical patients (especially those given ketamine) have also reported what was said and done during the operation, although they appeared to be unconscious (Schwender et al. 1997). 'Hovering above the scene' is a typical ketamine effect.
Some NDE's may involve re-experiencing the birth process in symbolic form. Grof (1988) was one of those who suggested that in the pre-birth 'amniotic universe', there are no boundaries and no time. Re-experiencing adults may interpret regressing to this level as ocean or the galaxy (for example), perhaps developing into an experience of cosmic unity. The feeling of 'coming home' relates to this level, a 'return from exile'. In the original birth process, 'paradise' is then disrupted by uterine contractions, but the cervix is closed so there is no way out. Contractions restrict the blood supply, producing the same chemical conditions in the brain that may trigger an NDE in later life. The symbolism is of engulfment and imminent disaster, the beginning of the hero's journey, expulsion from Eden and the experience of no exit or Hell: entrapment in a claustrophobic, endless nightmare from which escape is impossible. The person is 'cut off' by the contractions from outside contact. The contractions continue but the cervix dilates and the baby moves through the birth canal, struggling against suffocation and compression, with energy building up towards explosive release. There may be images of cataclysmic events, and the struggle may have sexual, aggressive, demonic, and 'fire' elements when it is re-experienced. This build-up of tension is followed by release as the child is born from the darkness into light. The successful 'rebirth' in the re-experiencing adult may involve visions of white or golden light, beautiful vistas, a sense of salvation, death and resurrection, arrival in paradise, God, and the self reuniting with the 'divine source in the universal energy'. The different stages may not be worked through sequentially, and any stage may be repeated many times. There are ketamine experiences matching all aspects of this model, some prominent psychoanalysts have claimed to regress clients to the prebirth level (e.g. Winnicott 1958), and the foetus can hear and remember sounds heard from 20 weeks after conception (Evans 1998) as perception and memory develop in areas once thought to be too primitive (e.g. the thalamus). As the NDE often has therapeutic sequellae, this suggests that safe induction of the NDE using ketamine may have therapeutic value. This treatment has been used with good results in alcohol dependence (Krupitsky & Grinenko 1997).
Brain cells bathe in dissolved salts that may wash in and out through tunnels in the cell wall. Ketamine binds to PCP receptors inside some of these tunnels and causes a blockage (Thomson et al. 1985). Glutamate crosses the gap between cells and binds to NMDA receptors on the other side (on the cell surface) turning the chemical key in the lock, but while the tunnel is blocked by ketamine binding to PCP receptors, no new impulse can be fired. Confusingly, the term 'NMDA receptor' is often loosely used for the whole complex, including the PCP receptor (Cotman et al. 1988). Ketamine also affects opioid, dopamine (it activates dopamine systems), serotonin, noradrenaline, nitric oxide, sigma, GABA (gamma amino-butyric acid, an inhibitory messenger), acetylcholine and endocrine systems, amongst others (e.g. Hustveit et al. 1995; Oyama et al. 1970; Lindefors et al. 1997; detailed review: Jansen 2000). These other systems may be considered when the effects of the drug are interpreted, e.g. kappa opioid receptors may contribute to the psychedelic effects (Pffeifer et al. 1986; Hirota et al. 1999). While ketamine produces NMDA receptor blockade, subanaesthetic doses may, in some tracts of the brain, actually release glutamate (Moghaddam et al. 1997; Anand et al. 2000) resulting in excitement via non-NMDA glutamate receptors such as kainic acid and AMPA receptors. At subanaesthetic doses, blocking the NMDA receptor complex also does not result in a 'switched-off brain' because the switched-off cell may have been one which releases the inhibitory GABA. If inhibition is removed, the next cell in the chain becomes excited (Drejer & Honore 1987). Thus the neocortex is 'hot' (hypermetabolic) in brain scans at psychedelic ketamine doses (Vollenweider et al. 1997a,b). At high doses, the brain is more likely to be calm, as in conventional anesthesia.
Both NDE's and ketamine experiences involve blockade of the NMDA receptor complex (Jansen 1989). Many factors, such as a sudden fall in O2 or blood sugar, a rise in CO2 (e.g. due to interruption of the blood supply during a heart attack), or 'spontaneous' factors cause a flood release of glutamate (Benveniste et al. 1984). This over-excites brain cells which die, bursting like over-inflated balloons ('excito-toxicity'; Rothman & Olney 1987). Ketamine can prevent this brain damage via the same mechanism which is central to its psychedelic effects: blockade of tunnels so that 'the sea' cannot rush in (Weiss 1986). This led to the prediction that the brain would have a natural protective mechanism against the glutamate flood (Jansen 1989; 1990a; 1997a; 2000) , probably a counter-flood of natural NMDA receptor complex blockers, producing ketamine-like NDE effects. While a person is having an NDE, the brain is thus protecting itself from excito-toxic damage. The existence of such natural glutamate blockers is now established. These include NAAG (N-acetyl-aspartyl-glutamate), magnesium and kynurenic acid, all of which protect cells from excito-toxic damage (Coyle 1997; Feldman 1996; Miranda et al. 1997). The endopsychosins (Jansen 1990a) proved to be a mirage. Those who were O2-deprived for long periods and had profound NDE's sometimes survived with unimpaired brains. This lack of damage may result from a very effective inherited mechanism for blocking over-excitation. Those who can have an NDE may be less likely to suffer brain damage (Jansen 1997a). These may be the same group who report psychedelic experiences with ketamine. About 40% of the population have had some form of NDE, when the widest possible definition is used including NDE-like phenomena during dreams (Sabom 1982). The % who report 'emergence phenomena' after ketamine anesthesia also averages about 40% across many studies. Dreams, ketamine 'journeys' and NDE's are all states in which there is a reduced input from the outside world. Those who do not recall their dreams are also unlikely to recall ketamine 'journeys'. In a study of 150 patients, 45% recalled dreaming at home (Hejja & Galloon 1975). Of these home dreamers, 75% described dreams during ketamine anaesthesia (50 out of 68), while only 2 of the 82 who were not home dreamers had dreams during the anaesthesia. The % of home dreamers is about the same as the % reporting 'emergence phenomena' in many anaesthetic studies: about 40%. Genetic differences may be responsible (e.g. Malhotra et al. 1998).
The same altered state of being may be reached by many different routes. The above hypothesis does not apply to every NDE, nor is it incompatible with a belief in 'life after life' as it limits itself to bodies that have not permanently ceased to live. The production of an NDE with ketamine does not necessarily diminish the meaning and value of the experience.
Ketamine blocks out the outer world, and sensory deprivation itself can result in 'out-of-body trips' (Lilly 1978). In many near-death situations, sensory input is cut off isolating parts of the brain from the setting. The now empty stage of awareness fills with new realities originating from the depths of the mind. The NMDA receptor is the link joining NDE's, Lilly's 'tank-trips' and ketamine 'journeys' together. Memories may be suppressed by a gate that admits external signals when we are concentrating upon an external task. If this input is cut by a sensory deprivation tank, ketamine, sleeping, a heart attack, or a spontaneous mental event (epileptic attacks can arise in a person at rest), for example, together with inner stimulation, stored memories and other material may be released and organised into a semi-meaningful drama . This has evolutionary value if the message is: 'it is not your time to die, go back!' or the re-infusion of a person's life with a sense of meaning, leading to improved health (Krupitsky & Grinenko 1997). NMDA receptors, a part of this gate, are dense in areas where data from the external world are integrated with the inner world (Jansen et al. 1989).