Your husband comes in the door, and you go to greet him. Suddenly, you stop. Why this man isn’t your husband at all. He looks just like your better-half, but no! That’s definitely not him. Or at least that’s what your brain thinks. This type of delusion is not what you are used to in normal day to day life. It is an example of Capgras syndrome. Many other delusion disorders are categorized as DMI or delusional misidentification syndrome. These disorders usually center around one idea and make the world a very strange place for the people who have them, as they see everyone in disguise or perhaps don’t even recognize their own bodies.
1. Deja vu
It isn’t exactly a delusional misidentification syndrome, but it’s just as disturbing as one. Deja vu happens to a lot of us. You see something and immediately feel like that is something you’ve seen before or done before. But some people have chronic déjà vu. They remember things which never happened, like already watching the news, going to a friend’s funeral, or meeting someone for the first time. For them, nothing is new. One man said he wouldn’t go to a doctor to find out what was wrong because he thought he had already been. But he hadn’t!
2. Frégoli syndrome or Frégoli delusion
Named after a quick-change artist, Leopoldo Frégoli, the Frégoli delusion or Frégoli syndrome leads people to believe that the people around them are actually other people in disguise. For example, you see your doctor and think that it’s your ex-girlfriend disguised as your doctor. One patient was convinced that two famous actresses put on the guise of her nurses and acquaintances to pester her [source: Edelstyn]. People with Frégoli delusion think that the people around them are capable of changing their appearance, dress, and gender in a matter of moments, with only nearly imperceptible clues to their real identity.
3. Cotard’s syndrome or Cotard’s delusion
Cotard’s syndrome refers to the belief that the person is missing one of their body parts or has become emotionally dead. Some people with Cotard’s think that they no longer exist because they don’t feel anything. It usually occurs in psychoses like schizophrenia and bipolar disorder. Patients’ complaints run from “My heart doesn’t beat” to “I think my brain is rotting. They think they’re the walking dead.
People with this syndrome think that familiar people in their lives have switched identities, both physically and psychologically. While Fregoli syndrome involves just a physical transformation, intermetamorphosis includes oneself. You might, for instance, decide that your mother is really your sister, and every time you see your mother, you see him as having the physical attributes of your sister.
5. Capgras delusion
Capgras delusion is a disorder in which a person holds a delusion that a friend, spouse, parent, or another close family member (or pet) has been replaced by an identical-looking impostor. It can occur in acute, transient, or chronic forms. Cases in which patients hold the belief that time has been “warped” or “substituted” have also been reported. Imagine how disturbing it would be to have someone who looks like a loved one sits down with you and know intimate details about your life, even though you’re sure that this person is an imposter.