Chapter 16

The Ketamine and Drug-Induced Experience Objection

Karl Jansen spent twelve years studying ketamine. He is a psychiatrist. He is also the man most often cited by skeptics who want to explain near-death experiences as a kind of drug effect. Jansen's own theory — that the brain releases a ketamine-like chemical during a crisis, producing NDE-like phenomena — became the gold-standard skeptical model in the 1990s.

Then Jansen changed his mind.

In a postscript to his own published article in the Journal of Near-Death Studies, he wrote that he had come to believe in a soul independent of bodily experience. Ketamine, he now thought, was not evidence that no such reality exists. Ketamine was a door — one of many doors — to a real place we cannot normally reach.¹

That is where I want to begin. Not because Jansen's later view settles the question. It does not. But because the most prominent architect of the ketamine-NDE model, after more than a decade in the lab, walked partway out of his own materialist conclusion. We will come back to Jansen at the end. First, the argument.

A. The Critic's Argument

Marsh devotes a long stretch of chapter 9 to ketamine.² His thesis is straightforward. Ketamine — a dissociative anesthetic introduced in the 1960s — sometimes produces experiences that feel a lot like NDEs. Patients coming out of ketamine anesthesia often describe floating outside the body, seeing colored shapes, sensing timelessness, gaining a sudden flash of insight, or feeling fused with other people or objects. Some describe traveling through colored rooms or going to "another world." If a drug can produce phenomena like that, Marsh argues, then perhaps the brain itself produces something similar during the crisis he calls an Experience of Clinical Endangerment, or ECE.³

Marsh draws on the work of Karl Jansen for the chemistry. Here is the picture in plain English. Brain cells communicate through chemical messengers. One of those messengers is glutamate. When the brain runs short of oxygen, glutamate floods the synapses, and that flood can kill cells. Jansen proposed that the brain has a built-in defense — a substance that blocks certain glutamate receptors (the NMDA receptors) the same way ketamine blocks them. The blocker keeps brain cells alive. As a side effect, it produces dissociative experiences that look like what survivors of cardiac arrest sometimes report.⁴

So the argument runs like this. We know ketamine produces NDE-like phenomena. We know oxygen starvation triggers a glutamate flood. We have reason to think the brain protects itself with a ketamine-like blocker. Therefore the brain's own chemistry under crisis is a plausible candidate for producing what we call NDEs.

To Marsh's credit, he is honest about the difficulties. He acknowledges that no naturally occurring "endopsychosin" — the proposed natural blocker — has been definitively isolated. He concedes there is little hard support for the radical version of the model.⁵ He notes that the dissociative episodes from ketamine are emergent phenomena, meaning they happen as the patient comes out of the drug, not in deep anesthesia. He even cites anesthetist Barbara Collier's finding that 60 percent of her ketamine patients did not wish to repeat the experience.⁶ A striking number that should make us pause. Marsh is not naive. He is saying ketamine is the best available paradigm, not a settled explanation.

Fischer and Mitchell-Yellin make a related argument when they discuss altered states.⁷ They are less interested in the chemistry and more interested in the experience. If dissociative drugs reliably produce experiences that feel transcendent, why suppose that spontaneous transcendent experiences during medical crisis are any more reliable as glimpses of an afterlife? The skeptical case, in either form, comes down to this: chemistry can apparently mimic the whole NDE package, so the burden is on NDE researchers to show that the experiences are something more than drug-like dissociation.

That is the argument. It deserves a serious response.

B. Identifying Weaknesses

The argument has three large problems before any positive evidence is even consulted.

First, the endogenous-ketamine claim is unsupported. Jansen himself called it the only speculation in his model. Decades later, no naturally occurring substance with the right profile has been confirmed. Marsh, to his credit, says the same.⁸ So the model rests on a hypothesized molecule — the missing piece — that has never been found. That alone should pause anyone tempted to treat the ketamine model as established science.

Second, similarity is not causation. Two experiences can resemble each other without sharing a mechanism. A vivid dream and a real memory can both feel real; that does not mean dreams and memories are produced the same way. A drunken stupor can produce slurred speech. So can a stroke. Same surface, different machinery underneath. Marsh's chapter slides smoothly from "ketamine experiences resemble NDEs" to "ketamine experiences may explain NDEs" — but that is a logical leap, not an inference.

Here a simple analogy helps. Imagine your radio is playing music. Now I take a hammer to the speaker. The music distorts. It garbles. It crackles. Now imagine I do something fancier — I rewire the inside, change the tuning, knock the knobs around. I can produce all kinds of strange new sounds. Have I just shown that the radio generates the music? Of course not. I have shown that the radio's output can be modified by tampering with the receiver. Damaging or chemically altering a brain modifies its output. It does not follow that the brain produces consciousness any more than the radio produces the music. We will revisit this filter-versus-production distinction in Chapter 23; it matters here because Marsh's whole argument quietly assumes the production model without ever defending it.⁹

Third — and this is the cleanest empirical problem — most ketamine experiences are nothing like NDEs. In Collier's well-known study of 131 patients, the most common phenomena were colored kaleidoscopic patterns, geometric shapes, watching multiple objects, floating down corridors, and, frankly, monsters. One subject saw a row of prehistoric monsters walking. Another watched animated cartoons. A third was convinced for two hours after surgery that he could speak Italian.¹⁰ None of that appears in NDE accounts. NDEs do not include cartoon imagery, geometric mosaics, or temporary fluency in foreign languages. The features of ketamine that are not shared with NDEs vastly outnumber the ones that are. Marsh almost makes this point when he concedes the troublesome differences — and then sets the concession aside.¹¹

So before we even get to positive evidence, the skeptical argument is wobbling. The chemistry is speculative. The inference from similarity to mechanism is invalid. And the actual phenomenology of ketamine is, on the whole, conspicuously unlike the actual phenomenology of NDEs.

C. The Pro-NDE Response

The Testimony of People Who Have Had Both

The most direct test of Marsh's hypothesis is to ask the people best positioned to compare. Those who have had both ketamine experiences and NDEs. Or, failing that, people who have had ketamine and have studied NDEs at depth.

Kenneth Ring, one of the founding figures of NDE research, took ketamine nine separate times in the course of his work. He wrote in a personal communication to Chris Carter that his trips were extremely variable and often transcendent — but that nothing he experienced, in content or texture, had any particular overlap with the classic NDE.¹² Most of the ketamine users he knew personally would say the same. Ring is not a skeptic of altered states. He has investigated NDEs more thoroughly than nearly anyone alive. And he says ketamine is not the same kind of experience.

Rick Strassman, a psychiatrist who has run extensive clinical trials on hallucinogens, says something similar. He notes that patients waking from ketamine anesthesia often describe their experience as fearful, not blissful — frightening enough that many do not want to repeat it. The emergence phenomena share some features with NDEs, but lack the equanimity, the sense of beneficial transformation, and the lasting decrease in fear of death that experiencers consistently report.¹³ NDEs change lives in a particular direction. Ketamine, by and large, does not.

This pattern — ketamine recall as scary and fragmented; NDE recall as peaceful and clarifying — runs through the clinical literature. Collier described the ketamine-induced sense of depersonalization as a common cause of profound fear, with some patients believing they had died or gone insane.¹⁴ NDE accounts almost never look like that. The classic NDE leaves the experiencer convinced they have brushed against a real, beautiful, deeper reality — and convinced about the value of life on this side of death.

The Veridical Perception Problem

Even if every other element of an NDE could be matched by ketamine, the model collapses at one point: veridical perception. We treated a number of these cases in Chapter 4 and the Pam Reynolds case in Chapter 5. Ketamine produces images. Sometimes vivid, sometimes terrifying, sometimes dreamlike. It does not produce accurate reports of real events the patient could not have witnessed by ordinary means.¹⁵ Nobody reports a ketamine trip in which they correctly described what their wife was doing in the next room. Nobody reports floating during ketamine and accurately reading a number off a shelf they had never seen. There are zero published cases of ketamine producing veridical perception of distant real events.

That zero is decisive. The ketamine model can, at best, account for the subjective phenomenology of an NDE. It cannot account for what makes NDEs evidentially powerful. And it is the veridical element that drives the case for substance dualism. Strip the veridical out of the NDE evidence and you have a fascinating subjective phenomenon. Leave it in, and you have something the brain — drugged or otherwise — should not be able to do.

The Confusion Problem

Peter Fenwick, a British neuropsychiatrist who has studied NDEs for decades, makes a crucial observation. Cerebral catastrophe produces confusion. Any physician who deals with head injury, epilepsy, or severe altered cerebral physiology knows this. Recovery from a faint is recovery from a confusional state. As the brain becomes compromised, it disorganizes. Patients coming out of cardiac arrest are routinely confused, disoriented, sometimes amnestic for events around the arrest.¹⁶

If NDEs were simply a chemical artifact of the dying brain — even a self-protective ketamine-like artifact — we would expect them to share that confusional character. We would expect fragmentary, disjointed, hard-to-recall experiences. Instead, NDErs describe a state of unusual clarity. They report thoughts running with greater speed and precision than normal. They remember the experience for decades, often in greater detail than ordinary memories. As Fenwick observed, this is exactly the opposite of what one would expect from a dysfunctional brain.

Set, Setting, and Special Pleading

Carter raises a problem the skeptical literature mostly ignores. NDE-like ketamine trips are reported almost exclusively in hospital settings, where the patient is already primed to interpret dissociation as "dying."¹⁷ Ring and the Fenwicks have noted that ketamine experiences in recreational settings rarely take on classical NDE form. The setting shapes the trip. By contrast, NDE phenomenology is consistent across radically different settings — battlefield, operating room, swimming pool, freeway crash — in patients who often did not know they were dying. If the experience required a hospital frame to take its NDE shape, that consistency would not exist.

There is also a problem of selection that Carter calls special pleading. The skeptic wants to keep the NDE-like portions of ketamine trips as evidence that brains produce NDEs, while discarding the cartoon-figure, geometric-pattern, monster-laden portions as mere drug noise.¹⁸ But what justifies that selection? Either the whole ketamine experience is brain output — in which case NDEs ought to include cartoon figures, which they do not — or the brain under chemical pressure is producing different kinds of phenomena, which is exactly what filter-model dualists have been saying.

Karl Jansen's Reversal

And here we come back to Jansen. After roughly a decade arguing the materialist version of his model in the medical literature, Jansen wrote a postscript at the end of his second article in a 1997 issue of the Journal of Near-Death Studies. He admitted his views had shifted. He said he was no longer as opposed to spiritual explanations of near-death phenomena as his earlier articles suggested. He said he had come to believe a soul exists independent of experience — that it begins when we begin and may persist when we end.¹⁹

I do not lean on this as proof. People change their minds, and Jansen is one man. But the materialist who built the model walked partway out of it after twelve years inside. That should at least make us cautious about the next confident claim that the matter is settled.

Greyson and the Specialists

Bruce Greyson, longtime editor of the Journal of Near-Death Studies and one of the most careful researchers in the field, has noted something striking. Of every large NDE study published in a mainstream medical journal, not one has concluded that NDEs are explainable as hallucinations. Not one.²⁰ That kind of agreement among working scientists is unusual. The researchers most familiar with the data are the researchers most reluctant to dismiss it as drug-like. The skeptical narrative has been kept alive largely by writers who have never run an NDE study themselves.

Pim van Lommel adds a complementary point. Every cardiac-arrest patient experiences the same physiological crisis, the same oxygen drop, the same potential glutamate flood. Yet only 12 to 18 percent report NDEs. If endogenous ketamine were the explanation, the rate should be far higher. The chemistry should not be optional.²¹

I will be brief on the dream connection because Chapter 15 handles it in depth. Long's research has shown that NDErs who have also experienced hallucinations or lucid dreams consistently distinguish their NDE as different in kind. They know what dreams feel like. They know what hallucinations feel like. The NDE, they say, is not in the same category. Subjects describe it as more real than real. That is not a quirk of language; it is a stable, repeated finding across studies.²²

Put it together. The chemistry is hypothetical. The phenomenology mostly diverges. The veridical perception cannot be reproduced under ketamine. The confusion expected from a drugged or dying brain is conspicuously absent. The pattern of selection in skeptical reasoning amounts to special pleading. And the architect of the model has himself stepped back from his own conclusion. The ketamine objection is not nothing. It is an honest attempt at explanation. But the evidence has not cooperated.

D. Counter-Objections

A skeptic with patience could still push back at two points.

"You are cherry-picking the differences." The skeptic might say I have highlighted the dissimilar features of ketamine experiences while waving away the genuinely NDE-like features. Some ketamine subjects do report leaving the body, seeing a light, feeling at peace, encountering presences. These features really do appear. Does that not show some shared mechanism?

It shows shared features. It does not show shared mechanism. Two phenomena can produce overlapping outputs while running on different machinery. A photograph can resemble a painting; that does not make a camera a paintbrush. The proper test is not whether some ketamine experiences share elements with NDEs. The proper test is whether ketamine can do what NDEs do. And on the decisive criterion — accurate perception of real events the experiencer could not have known by ordinary means — ketamine has never been shown to do it.

"But endogenous ketamine could still be discovered." True. The model is in principle still alive. Some future study might isolate a natural NMDA-blocker that floods the brain in crisis. That would be an interesting finding. But it would not solve the deeper problems. The absence of veridical perception under any drug. The lucidity inconsistent with cerebral compromise. The radio-style filter alternative that fits the data at least as well. Even if endogenous ketamine were confirmed tomorrow, the skeptic would still need to explain clear perception during a compromised brain state. Discovering the chemistry would not, by itself, settle whether the brain produces the experience or whether the brain, functioning under that chemistry, is a more porous filter than usual.

What this chapter has tried to show is simple. The ketamine objection sounds strong because it sounds scientific. When you look at it carefully, it is mostly speculative chemistry stretched over a phenomenological mismatch. The next chapter takes up a related concern that is even more pressing for the dying-brain model: the timing problem. When exactly do NDEs occur — and can the residual brain activity at any plausible window account for what experiencers report?