The Real-Life Walking Dead

Cotard's syndrome, also known as Walking Corpse Syndrome, is a rare disorder that causes sufferers to believe they are dead. The exact cause is unknown. Doctors Thomas Linden and Andres Hellden describe effects of the syndrome that they observed in patients who took a common antiviral medication.

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IRA FLATOW, HOST:

This is SCIENCE FRIDAY.

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FLATOW: And for this hour at least, I'm Ira Frightow. It's our annual Halloween edition, the spooky side of science, from green slime to psychopaths walking among us to the naked mole rat.

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FLATOW: First up, something for you "Walking Dead" fans. In this case, Walking Corpse Syndrome, where the person thinks he is dead, but of course is not. Creepy, no? It's called Cotard Syndrome and no one is quite sure how this rare disorder works or what causes it, but two doctors in Sweden have observed it as a side effect of a common antiviral medication.

And they've only seen it in about a handful of patients. Their findings were recently published in the Journal of the Neurological Sciences and they're here to tell us about this intriguing syndrome. Thomas Linden is a neurology senior consultant at Sahlgrenska University Hospital, associate professor at the Institute of Science and Physiology at Gothenburg University in Goteborg, Sweden. Welcome to SCIENCE FRIDAY.

THOMAS LINDEN: Thank you. Thank you so much.

FLATOW: You're welcome. Anders Hellden is a consultant at the Department of Clinical Pharmacology at the Karolinska University Hospital in Stockholm, Sweden. Welcome to SCIENCE FRIDAY.

ANDERS HELLDEN: Oh, thank you for inviting us, yes.

FLATOW: Anders, Thomas, do people really think they're dead? What do you mean by that?

HELLDEN: Well, they express very strongly that they are dead. When nurses and physicians meet them in these acute situations when they had developed acyclovir toxicity, they expressed a very strong feeling of being dead. And they say it's no use talking to me, I'm dead.

LINDEN: And this is a syndrome that was described originally about 100 years ago, a little more than that, and before our findings it was considered a very rare disorder and appearing in connection to severe stress, and that could be emotional stress like severe depression or bipolar disorder or schizophrenia, but also bodily stress like dehydration or malignant disease or migraine or infectious disease.

FLATOW: How do you say I am dead? Who knows what it feels like to be dead?

HELLDEN: That's a very intriguing question. We don't know. They only express this and it's a very strong feeling, so we can read about it in the patient charts and they just say that, I'm dead. And we have met at least two patients that have developed this and they express a very strong feeling of being dead.

FLATOW: Do they - they can't feel their limbs, do they not eat, or what - how do they manifest this?

HELLDEN: Well, this is a very acute situation. They receive acyclovir because treating the shingles or zoster. Usually it's zoster. So they get the drug and probably they get too much. The doses are too high. They have renal impairment or renal failure and when they start to use the drug, they can take only three tablets of acyclovir and they start to develop this.

And then they get into a kind of state where they start to have nightmares. They are very - they start to be anxious and maybe within 24 hours they start to feel that they are dead.

FLATOW: Can you reverse this?

HELLDEN: Yes.

FLATOW: How?

HELLDEN: Well, there are two ways. You stop the treatment. That's the first way. The second way, if you still have some kind of renal function, you can increase the urinary output of acyclovir and its metabolites. And if you're an end-stage renal disease patient, you have dialysis, you perform a hemodialysis and then the symptoms disappear within - in sometimes one or two or three hours during the dialysis.

FLATOW: Now, Dr. Linden, I understand that one of the most remarkable things about this syndrome is that they're able to reason with you. I mean they don't have a death wish. I've read that people have starved to death from this.

LINDEN: Well, these people, they are very convinced that they do not exist, but instead they are rather convinced the opposite and feel very strongly that they are dead. There is also a variance of it that they are drained of blood or they have been stripped of their inner organs or other variations on the same theme.

But you can reason with them and they can intellectually conclude that it's really not likely when I'm standing here and talking to you that I am dead, but the conviction is much stronger too than the intellectual reasoning. And that's so strange, weird for anyone witnessing them expressing this.

FLATOW: Yeah, 'cause they obviously have an intellectual conflict with what their emotions are telling them.

LINDEN: Yeah. And because of that, Cotard is maybe one of the few delusions that does not need verification, as the phrase "I am dead" said by the patient actually confirms the delusion by itself.

FLATOW: Do you think that this has happened years ago, before there was the medication that produced it, that it may have happened some other way?

LINDEN: Well, it has been described in the 1880s for the first time systematically, but it was long thought to be a very rare disorder, but we have reason to think that Cotard is more common than previously thought, since I, for my sake, have heard references to other cases whenever I mention the condition in my lectures, and I think maybe the condition is so strange that we tend to interpret it as something we know better, as death wish or suicidality, but these patients, they do really not wish to die.

Most are terrified of the knowledge that they don't exist and frightened to be buried or cremated or to be doomed to walk among the living without really belonging here. But they are really, really suffering patients.

FLATOW: So they don't really have a sense of humor about the situation that they're in, thinking that...

HELLDEN: Quite the contrary, really. They're suffering.

FLATOW: And there's no way you can talk them out of it, as you say. They can look at themselves in a mirror, they can see that they're alive, but they think they're dead.

HELLDEN: They can reason about the unlikeliness that they should be dead, walking and standing, but still they are very convinced about it. And that's so intriguing because it tells us something about the function of consciousness that we have, that we may be - not be thinking of in everyday life, but once we miss it, then we really feel that something is not as it should be.

FLATOW: Thomas, some people compare it to a Capgras syndrome. What is this?

LINDEN: We have other disorders actually involving consciousness, and in our material, the one that we just recently published, we have seen two patients with what we call alien hand syndrome in connection to Cotard syndrome after acyclovir treatment, and alien hand syndrome is a part of the hemispatial neglect spectrum disorders, which appears maybe most commonly in stroke patients who have had their injury in the parietal lobe, which is in the brain just back of the top of the head. In a stroke, maybe 20 percent of the patients suffered from neglect, as we commonly call it. And the most common - most commonly the damage is in the right lobe, and it's quite common.

And the patient experiences an inattention towards the opposite side of the body, and the patient does not as easily then recognize anything coming from that direction. And that affects also the recognition of their own body and the sense of it belonging to yourself. And as we normally intrinsically feel that, for instance, that the hand is a part of the body and not just like the wristwatch, that we have something that is attached to it, the patient with the alien hand syndrome strongly feel that the hand, wrist or arm does not belong to them, that it's stuck to the body. And they may also try to get rid of it. So in contrast to Cotard syndrome, which is a failing consciousness of existing, alien hand is the failing consciousness of what is your body and what is not.

FLATOW: Anders, have you spoken to many patients who've had this?

HELLDEN: Not personally. My former supervisor met a patient at a dialysis unit, and she spoke to the patient. I've spoken to other patients with hallucinations and acyclovir toxicity. I've actually been fighting with one of them, because he was so agitated. So I've met several patients, not with Cotard syndrome, but with other acyclovir toxicity syndromes or symptoms.

FLATOW: And Thomas, what do you think the prognosis of this whole industry is, or the whole field, here?

HELLDEN: I think the most intriguing about all this is that we finally get a piece of the puzzle of understanding how consciousness works. And, for instance, that the observation of one patient with Cotard syndrome having dialysis and improving, and experiencing alien hand syndrome before totally recovering, is a strong clue that these two forms of consciousness are functionally related to each other. And we also know which part of the brain is damaged when we see neglect disorder. So that is a clue to what actually might cause Cotard syndrome.

FLATOW: Are these patients bedridden, or do they still get around?

LINDEN: They walk around. Yeah.

FLATOW: They walk around, but they think they're dead.

LINDEN: Yes. The patients I've heard about and the patients - the other patients with toxicity I've met, they walk around, yes.

FLATOW: And how do the families treat them?

LINDEN: The families are very concerned about their condition, so they - usually, they come with a parent or with a child to the emergency ward to seek for help. Because they see something is happening within a few hours, or 24 hours or something, after they start the treatment for, for instance, shingles.

FLATOW: Gentlemen, thank you very much for taking time to be with us today. Thomas Linden, a neurology senior consultant at Sahlgrenska University Hospital. And also Anders Hellden, consultant, Department of Clinical Pharmacology at Karolinska University Hospital in Stockholm.

LINDEN: Thank you.

FLATOW: Thank you. We're going to take a break. When we come back more, we're going to talk about the psychopath amongst us, not just walking, but maybe sitting right next to you. Stay with us. We'll be right back after this break. I'm Ira Flatow. This is SCIENCE FRIDAY, from NPR.

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