Today we explore one of the strangest corners of abnormal psychology: delusional misidentification syndromes. In Who Was Martin Guerre, we learned that the process of recognition of identity is a delicate one. And that’s when all involved parties are healthy! Certain neurological disorders make recognition of identity a much more difficult prospect, and the consequences are quite bizarre.
Though not actually a delusional misidentification syndrome, we should begin with prosopagnosia: the inability to recognize all faces. Note that the vision of prosopagnosics is completely unaffected; they may have 20/20 eyesight. It’s the ability to recognize faces in particular that’s impaired. This is possible because vision in general is processed in the lateral geniculate nucleus and in the visual cortices. Faces, on the other hand, are processed in an entirely different area: the fusiform gyrus, also known as the fusiform face area.
Prosopagnosia is fairly common. It may result from brain damage (acquired) or it may exist from birth (congenital); in fact, about 2.5% of the population suffers from congenital prosopagnosia. Prosopagnosics aren’t entirely without hope. They often assess identity by assembling facial features “piecemeal” (full lips, pronounced cheekbones, green eyes, brown hair; looks like Mary). Further, they use clues like clothing, gait, and voice; note that ability to recognize identity from voice is generally unaffected. Still, prosopagnosics often report difficulty with social interaction in general, since the inability to tie face to identity makes it difficult to keep track of relationships.
Interestingly, prosopagnosics also tend to suffer from topographical disorientation, a characterized by an inability to become familiar with one’s environment and to use landmarks. So, maybe the fusiform face area isn’t just for faces. Perhaps it coordinates the general ability to tie several components together and instantly recognize the whole.
Now, for the misidentification syndromes:
A student at UCSD was injured in a car crash; he spent a few weeks in a coma. Upon waking, he seemed to be doing fine, except for one strange detail: when his mother visited him at the hospital, he swore she was an impostor! “She looks just like my mother,” he admitted, “but she’s just not my mother. Something’s not right.” He thought the same of his dad and of all his other friends and family; they had all been replaced by doubles.
What happened here? Well, his ability to recognize faces was fine (note that Capgras Syndrome does not represent acquired prosopagnosia), as was his ability to feel emotion. But the connection between these two respective brain areas—the fusiform gyrus and the amygdala—was severed. Before the accident, he’d recognize his mom’s face, feel the emotional connection he was used to feeling when he saw her, and go on with his day. Now, though, he’d see his mom, but not feel the customary emotional response. Thus his only possible conclusion was that she wasn’t his mom in the first place. As Carol Berman, psychiatrist at the New York University Medical Center, describes the delusion: when the patient views a person, “it’s as if the soul of the person isn’t there” (1).
To provide confirmation for the aforementioned theory: when the student talked to his mom or dad on the phone, he was fully convinced it was them! Thus, only the route between vision and emotion was damaged.
Capgras syndrome can result from brain trauma, as in this case, but more often, it comes along with schizophrenia.
Fregoli syndrome, or the delusion of doubles, is the belief that several people within one’s life are actually all the same person, assuming multiple identities via disguise. Even multiple objects, places and events can seem to the observer to be one and the same!
Fregoli syndrome, like Capgras, often comes with schizophrenia. Also, like Capgras, it can be induced by traumatic brain injury. Distinct form Capgras syndrome, though, is the fact that Fregoli syndrome can result from damage to the fusiform gyrus. It makes sense: in Capgras, the ability to recognize faces is fine; only the emotional response is impaired. In Fregoli, though, the fusiform gyrus might have a lower threshold for recognition. Thus it sends the “recognition” signal to the amygdala even if the recognized face does not belong to the usual producer of that emotional response. To the observer, multiple faces produce the emotional response usually reserved for just one, and so all of those people seem to be the same.
Shockingly, antiparkinsonian medication is also one of the leading causes of Fregoli syndrome!
Also interesting is that, especially in cases of Fregoli syndrome alongside schizophrenia, the delusions are often persecutory in nature. In other words, one master of disguise is using his false identities to chase the observer. Finally, especially in schizophrenics, Fregoli syndrome is sometimes seen together with Capgras. Imagine the horror!
People in the observer’s environment swap identities and/or appearances. One woman, suffering from bipolar disorder and depression, said that her abusive husband was using his powers of intermetamorphosis to “play tricks on [her] mind” and manipulate her. Both of her parents had been dead for 10 years, but her husband would regularly change into her father, or her mother, or even both at the same time. “He dresses up like them, changes his face and voice, and tries to tell me what to do,” she said. No other psychotic symptoms were found; she was not schizophrenic (2). One of the very few possible explanations was that the woman underwent several cingulotomies in order to treat her depression. However, cingulotomy offers a brief recovery period and has not been known to produce neuropsychological side effects. How incredibly bizarre.
I’ve mentioned only a few delusional misidentification syndromes; there are many more (see source 3). They only get stranger from here, and often, patients combine symptoms from several. Misidentification syndromes can be quite difficult to classify. Some scientists, though, claim a single common element: anomalies of familiarity. In pretty much any misidentification syndrome, including the ones described here, patients don’t feel familiarity when they should, or feel familiarity when they shouldn’t.
In fact, I think there’s a misidentification syndrome we’ve all experienced at least once: déjà vu. You think that you haven’t been here before. Yet, somehow, you feel that you have. You feel familiarity when you shouldn’t.
Misidentification isn’t as rare as we think. Our grip on reality is a fragile one indeed.
References and Further Reading:
- Seeing Impostors: When Loved Ones Suddenly Aren’t
- A New Identity for Misidentification Syndromes
- Delusional Misidentification Syndrome
- Capgras Syndrome
- Fregoli Syndrome