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Imagine opening your eyes tomorrow morning and realizing that you died in your sleep. It's not like in a horror movie; you're not a ghost or a zombie.

You're just very, very sure that you're not alive anymore, even though you're still walking and talking. That's Cotard's Syndrome. First described in 1880, people with Cotard's Syndrome believe they're dead, never existed, or that parts of their own body have spontaneously vanished or been destroyed.

It's rare, and there hasn't been a whole lot of research into it. But studying Cotard's Syndrome has helped psychologists gain a better understanding of how our brains create what we consider reality. According to case reports, being dead is a very stressful experience.

It dominates everything in your life— socializing, self-care, and even eating become far less important when you're no longer part of the land of the living. And the fact that your friends and family don't seem to notice only adds to the anxiety. In one case published in a 2009 study, an 88-year-old man was admitted to the hospital for a severe depressive episode.

He explained that he was depressed because he had passed away recently, but none of the people he knew had bothered to bury him. In another case from the same study, a 46-year-old woman explained that she was ‘a body without content'— that her brain and intestines had vanished, and that she was translucent. She refused to bathe because she believed that she was soluble, and her body might wash away if she did.

Cotard's is very distinctive, but it's not listed as a standalone disorder in the DSM 5, the guide mental health professionals use for diagnosis. Instead, it falls under the category of somatic delusions— untrue beliefs about the body— and is usually seen as a rare symptom of depression and psychosis. That makes it hard to estimate the exact prevalence of Cotard's, but we know it's uncommon, and seems to become slightly less rare as people get older.

One study looked at two years of general psychiatric admissions to hospitals in Mexico and found that only around 0.62% of patients exhibited Cotard's. And another, which looked at the elderly population in Hong Kong, found that around 3.2% of those with severe depression showed symptoms of Cotard's. Psychologists still don't know exactly how the delusion develops, but understanding the root of Cotard's Syndrome can help them piece together the psychological and neurological components behind our connection to our body … and our sense of being alive.

Research suggests that the symptoms most likely come from problems with the parts of the brain associated with facial recognition and emotional response. When you look at another person, or even yourself, a bunch of separate areas of your brain work together to process the specific physical features of that person, and your memories associated with them, bringing it all together into one complete perception. With Cotard's, scientists think the part of the brain that connects those bodily perceptions to previously established emotions isn't working the way it's supposed to.

It's likely that when people look in the mirror and recognize their own face but feel no emotional connection to it, their brain misinterprets that disconnect as a more fundamental change. And people with depression might be more likely to believe that this intangible change must mean they've passed away. But not all patients— not even all depressed ones— with this kind of disconnect between recognition and emotion exhibit Cotard's Syndrome.

That's where the association with psychosis comes in. Psychosis is when someone loses touch with reality, which means their rational thinking is impaired. And it takes that kind of cognitive impairment to believe something that's obviously not true.

Since someone with psychosis isn't thinking rationally, they don't automatically reject that gnawing “I must be dead” feeling they get when they don't feel emotionally connected to their own reflection. So once they realize something feels unfamiliar about themselves, they end up with a prolonged, upsetting delusion that they're dead, instead of shrugging off the idea as impossible. Since Cotard's Syndrome is fairly rare, there haven't been any clinical studies on the best way to treat it.

Doctors usually treat Cotard's similarly to psychotic depression— with a combination of medications, and sometimes electroconvulsive therapy, which uses electricity to stimulate the brain. Sometimes it works; sometimes it doesn't. This is one of those illnesses that reminds us just how powerful and bizarre the brain is.

It's hard to imagine losing the feeling that you're still alive. But studying Cotard's Syndrome can teach us a lot about our brains: the emotional connection that preserves our sense of being alive, and how losing that connection can make someone believe they've died. And hopefully, with more research, we'll also find better ways to treat it.

Thanks for watching this episode of SciShow Psych. If you're interested in learning more about how our minds work, you can go to youtube.com/scishowpsych and subscribe. [OUTRO ♪].