(Francesco Bongiorni for The Washington Post)

On Nov. 5, 2013, Esmé Weijun Wang came to the remarkable conclusion that she was dead.

In the weeks prior to this, she had begun to feel increasingly fractured — like being scatterbrained, but to such an extreme that she felt her sense of reality was fraying at the edges. She had started to lose her grip on who she was and on the world around her. Desperate to fend off what appeared to be early signs of psychosis, Wang went into a soul-searching and organizational frenzy. She read a self-help book that was supposed to help people discover their core beliefs and desires; she ordered and scribbled in five 2014 datebook planners, reorganized her work space and found herself questioning her role as a writer.

Then one morning, Wang woke her husband before sunrise with an incredible sense of wonder and tears of joy to tell him it all made sense to her now: She had actually died a month before, although at the time she had been told she merely fainted. (During a flight home to San Francisco from London, Wang had drifted into and out of consciousness for four hours. Afterward, doctors were unable to find a cause for this episode.)

“I was convinced that I had died on that flight, and I was in the afterlife and hadn’t realized it until that moment,” said Wang, now 32, who was convinced her husband and their dog Daphne were dead as well. “That was the beginning of when I was convinced that I was dead. But I wasn’t upset about it, because I thought that I could do things [in my life] over and do them better.”

Her husband assured her that she — and he — were very much alive, an assertion she dismissed. But as the days passed, her bliss turned into total despair. She lost all desire to work, talk or eat — because what’s the point when you’re already dead?

For almost two months, Wang suffered from Cotard’s syndrome, in which patients think they are dead or somehow nonexistent. Any attempts to point out evidence to the contrary — they are talking, walking around, using the bathroom — are explained away. French neurologist Jules Cotard first described the syndrome in the 1800s as a type of depression characterized by anxious melancholia and delusions about one’s own body. In a case report published in 1880, Cotard wrote of a 43-year-old woman who “affirms she has no brain, no nerves, no chest, no stomach, no intestines . . . only skin and bones of a decomposing body.”

A matter of misdiagnosis?

Although the condition is not classified as a separate disorder in the American Psychiatric Association’s Diagnostic and Statistical Manual of Mental Disorders, there have been plenty of anecdotal accounts of what has been sensationalized as “walking corpse syndrome” and “life as a zombie.” Doctors who treat the condition say Cotard’s syndrome is a real illness, with patients believing they are dead and, like Wang, feeling extremely depressed, anxious and suicidal.

“Patients truly experience all kinds of suffering,” said an expert in the syndrome, psychiatrist Jesús Ramírez-Bermúdez at the National Institute of Neurology and Neurosurgery of Mexico.

When he was a medical student working in a psychiatric hospital more than two decades ago, Ramírez-Bermúdez says, he saw patients who had been diagnosed with schizophrenia after they had said that they were already dead or that their bodies were disappearing. But after doing some research and speaking with other physicians, he came to the conclusion that they instead had Cotard’s. Since then, he has treated 14 patients with the condition, using both psychotherapy and medication.

One of his first cases was a man who claimed he was dead but also had delusions of having a twin brother who was alive. The patient frequently attempted suicide, once throwing himself out of a moving car.

“He would say that he had thrown himself out of the car because he thought that he was trapped in an eternity in which things were not real, and he was not real,” Ramírez-Bermúdez said. “He also felt that perhaps by dying [again] he would recover his former self.”

As for Wang, she found herself in a place that looked just like her old life but evoked no emotion in her, which led to anxiety, fear and agitation. She frequently descended into catatonic psychosis, a condition marked by periods of not being able to move, interspersed with overactive movement.

“I began to believe I was in perdition, or some kind of hell,” said Wang, who wrote an essay, “Perdition Days,” during and after the experience. “I was trying to figure out what I had done wrong, what had condemned me to this afterlife that looked like my real life before I died but wasn’t real — that was the torment of it. I kind of described it once as feeling like I was on fire inside.”

Debate over delusions

What causes Cotard’s syndrome and other delusions is a matter of debate. Delusions are seen in association with a wide range of neuropsychological conditions including dementia, schizophrenia, Parkinson’s disease and brain injury — and just as diverse are the nature of the delusional beliefs.

For example, when someone with self-misidentification looks at his reflection, he believes the person in the mirror is some stranger who looks just like him.

One of the better-studied delusions is Capgras syndrome, the belief that a spouse, family member or friend has been replaced by an identical-looking impostor.

What could cause such odd yet specific delusions? The leading theory suggests that two types of brain impairment are involved. The first alters the patient’s normal functioning — say, brain damage that prevents the normal processing of emotions when looking at familiar faces. The second, thought to be the same as in any delusional belief, is responsible for the patient’s lack of reasoning. It is what encourages the patient to hold on so tightly to his outlandish beliefs.

In stark contrast to healthy people, those with Capgras syndrome have been found to feel nothing when shown photos of their loved ones — a result of the first impairment. A person with Capgras thinks these people aren’t who they say they are and must be impostors. But for a person with Capgras to keep believing this no matter how bizarre it may sound, experts say, there must be some sort of damage in the right dorsal lateral prefrontal cortex, an area of the brain that deals with reasoning — this is the second impairment.

“You have one impairment that prompts the belief that, for example, this isn’t your wife. The second impairment is of your normal ability to evaluate beliefs, and accept or reject them,” said Max Coltheart, an emeritus professor of cognitive science at Macquarie University in Australia and a pioneer in the two-impairment theory. “When it comes to Capgras delusion, there are a number of cases in the literature in which the patient has murdered people who challenged the delusion. One boy thought his father was a robot and beheaded him to find the microchips.”

Lack of emotional response

The two-factor theory has been much less explored in Cotard’s syndrome, but Coltheart expects it would hold.

For Cotard’s patients, he thinks the first factor could be a failure to react emotionally to anything, not just familiar faces. Such things as loud noises, disturbing imagery or sudden touches that would typically elicit an emotional response would have no effect. In such cases, people may assume they are dead or no longer exist.

“It might be your favorite cat or your favorite food: If you don’t have an emotional response, that would be really weird,” Coltheart said. “Here is something that looks like your favorite cat, but you aren’t getting a buzz. If you were dead, you wouldn’t be getting any emotional responses, and that’s what may prompt this belief.”

In her essay, Wang describes being in such a harrowing state: “I was doomed to wander forever in a world that was not mine, in a body that was not mine; I was doomed to be surrounded by creatures and so-called people that mimicked the lovely world that I’d once known, but . . . could evoke no emotion in me.”

What caused her Cotard’s syndrome to surface is unknown. Earlier in 2013, Wang had been diagnosed with a form of bipolar-type schizoaffective disorder, but she believes the delusion may have been a result of Lyme disease long left untreated. She experienced symptoms consistent with Lyme disease for years, but it wasn’t diagnosed until 2014, after a writer who was interviewing her suggested that she get tested.

“I’ve been diagnosed with a case that is neurological, and I wouldn’t be surprised that this bacteria had something to do with my psychotic experiences,” she said, referring to Borrelia burgdorferi, the bacterium that causes the infection. Lyme disease can have severe neurological consequences, including inflammation of the brain and spinal cord, and has been associated with dementia, schizophrenia and depression. “[My Lyme disease] was really flaring up at the time the delusion arose, and I think the two are likely related,” she said.

There have been no reported cases of Cotard’s syndrome linked to Lyme disease, and Coltheart says the infection typically doesn’t affect cognition. But Ramírez-Bermúdez has seen a delusion that appeared to have been caused by inflammation of the brain due to a viral infection. The patient later had a complete recovery and gave Ramírez-Bermúdez a detailed account of the Cotard’s experience.

Although Wang is now receiving medical treatment for Lyme disease, the passing of her Cotard’s syndrome occurred before her Lyme infection was discovered. The recovery didn’t appear to coincide with any particular treatment or intervention. Less than two months after she first woke up with her delusion, the feeling of being dead faded.

“[The delusion] lifted completely without fanfare. There was no beam of light from the heavens; I was just going along and somebody pointed out that I was acting different,” Wang said. “I realized I thought I was alive.”

Ramírez-Bermúdez has seen cases of Cotard’s syndrome lasting only days or weeks, with a minority of patients showing chronic Cotard’s for months or years. The original case of Jules Cotard was a member of the latter group, until she eventually died of starvation.

After the delusions were gone Wang still felt fatigue, weakness, insomnia and joint pain — possibly the effects of her late-stage Lyme disease — but no longer did she see herself as a rotting corpse. Once again, she was able to feel the full spectrum of emotions experienced by people living in the real world.

Kim is a freelance science journalist in Philadelphia who is a regular contributor to The Post.