DEADLY SERIOUS
By Stephen Pincock
Wednesday, December 06, 2006
One autumn day roughly two years ago, a young woman was brought into Ryan McKay's office at a London hospital, sobbing bitterly, clearly very distressed and upset.
At that time, McKay's job was to administer specialised psychological tests to people who had been admitted to the hospital, to help provide neurologists with a better picture of their patients' brain functions. The woman, who we'll call Liz, was in hospital to seek help with serious and prolonged epileptic seizures, but when she was wheeled in to see McKay that morning, she was obviously suffering something much more disturbing
"She was completely preoccupied with the thought that she was dead," he recalls. "She kept saying that she'd died two weeks before and was worried about whether my office was heaven or not."
The young scientist realised that Liz was suffering from a rare and strange condition known as Cotard syndrome, which for the sake of brevity I'll define as the delusion that one is dead. The condition was named after the French psychiatrist Jules Cotard who wrote about some classic cases in the late 1800s. He called it delire des negations and described a host of other symptoms including feelings of guilt, denial of body parts and even, paradoxically for someone who thinks they are dead, thoughts about suicide.
The condition is sometimes seen in patients with schizophrenia or bipolar disease, but also in patients who have suffered brain damage, for example stroke. Liz, it turned out, had developed epilepsy as a result of herpes simplex viruses entering her brain.
Roughly 100 cases of Cotard delusion have been reported in the medical literature, which certainly makes it rare, although not as rare as some other strange delusions, such as the single case of a man with "perceptual delusional bicephaly". He believed he had two heads and was admitted to hospital suffering gunshot wounds from where he'd tried to shoot one off.
McKay started doing his best to carry out the tests on Liz. It wasn't an easy task, though. "She was pretty difficult to engage at first. Her eyes were darting around the room and she was really frightened and upset," he recalls.
Eventually he did get through, and posed a series of questions to assess an aspect of her personality known as her attributional style. Broadly speaking, this measures a person's tendency to attribute events in their lives to themselves (internal attribution) or to other people or luck (external).
He asked Liz a standard set of questions, presenting her with a range of scenarios - for example, a friend sending her a postcard - and asking her to think about the most likely cause of that event, whether it be herself, other people or chance.
The results showed that Liz had a significantly higher number of internal attributions than usual. This was interesting because it relates to one of the prevailing theories about what happens to patients with Cotard delusion. Scientists think that patients with Cotard syndrome have suffered some kind of disruption to the brain wiring for recognising faces. "The idea is that there are two elements to the visual recognition system," McKay explained to me over the phone last week from his new office at Australia's Charles Sturt University. The first element does the pattern-matching business of recognising a face, the second provides the more emotional buzz of familiarity.
In recent years, the UK researcher Andy Young and his colleagues have suggested that people with Cotard delusion have some kind of malfunction in the second of those elements. In fact, exactly the same breakdown is thought to occur in another sad and bizarre condition known as Capgras delusion, where patients believe that a loved one has been replaced with a physically identical impostor.
There's some evidence to support this idea. Specifically, when patients with Capgras are shown pictures of familiar faces while they are hooked up to a machine that measures physical signs of emotion, they show no greater response than if they were presented with the photo of a stranger.
The difference between people with Cotard and Capgras may come down to their attributional style, Young thinks. That is, they both have damage to the brain wiring responsible for the emotional component of face recognition, but they respond to this in different ways. According to this theory, when a patient with Capgras delusion experiences discordance between the way someone "looks" and the way they "feel", they attribute this to external causes: "That woman may look like my wife, but she's actually a physically identical impostor."
For patients with Cotard delusion, on the other hand, they attribute the same odd experience to themselves: "That woman looks like my wife but doesn't feel like her - it must be because I'm dead."
McKay's work with Liz, which has been accepted for publication in the journal Consciousness and Cognition, certainly lends experimental support to Young's ideas. Unfortunately, it doesn't tell us precisely what wiring had gone wrong in her brain.
Researchers are currently trying to figure out which parts of the brain are involved in these mysterious conditions. In the case of Liz, though, we may never know - a week after his first consultation with her, McKay visited her hospital room and found her vastly better. That was the last he saw of her.
