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4 Rare Psychological Syndromes You’ve Likely Never Heard Of

Prosopagnosia, Capgras syndrome, and more.

Key points

  • Social media is full of pop psychology terms, but there are lesser-known disorders that deserve attention.
  • Pica is a disorder in which a person habitually consumes non-food items.
  • Prosopagnosia is the inability to recognize faces.
  • These conditions, though uncommon, are authentic and can be difficult for those who experience them.

On social media these days, if you show any interest in human psychology, you’ll get bombarded with the kind of vocabulary that used to be found only in the therapist’s office. Words like narcissist, boundaries, validation, and triggered have proliferated on TikTok, Instagram, and other networks. Even when these terms aren’t used correctly—most of the time—it’s good to see a growing public interest in psychological understanding.

However, many real but less common psychological concepts still haven’t made it into the mainstream. To balance this out, I’ve put together a short list of real psychological phenomena with which most social media abusers probably remain unfamiliar.

Charles Bonnet Syndrome

An onset of powerful, strange, frequent, and uncontrollable visual hallucinations, Charles Bonnet syndrome is most often experienced by people adjusting to a significant loss of vision (like macular degeneration). Simply put, they see things that aren’t there but in full, brilliant color and detail. These hallucinations will vary in content but may include strange visions like fantasy animals, people dressed in elaborate costumes, exotic animals, or insects.

Other hallucinations reported by Charles Bonnet patients have included spectacular landscapes, including tall mountains or waterfalls, or just patterns of brightly colored lines, dots, or shapes. These visual oddities are very likely caused by the brain’s effort to cope with the sudden loss of the ability to see, and the disorder is most frequently found among elderly people—most likely because, as a group, they suffer from degenerative problems with vision more than any other age group.

Although they may be strange, the hallucinations aren’t psychotic in nature—meaning, they are not associated with a loss of contact with reality. People with Charles Bonnet syndrome know that their hallucinations aren’t real but may choose to hide them from others in their lives for fear of coming across as mentally ill.

Capgras Syndrome

It’s a common enough story in science fiction movies and TV: Someone close to the main character has been replaced by an impostor who looks exactly the same and knows everything the original would know but is secretly an identical double.

This high concept is also the core feature of Capgras syndrome—also known as the “delusion of doubles,” in which a person develops the intractable false belief that someone they care about has been replaced by a perfect duplicate. (A pet or an inanimate object, like a piece of art, clothing, or a household object, may also appear to have been replaced in this way.)

Capgras syndrome takes the form of a fixed delusion. No matter how logical your reasoning, you probably won’t be able to explain to a sufferer of Capgras syndrome that they are mistaken. This disorder’s prevalence is something like 0.12 percent of the population, and it often occurs in patients with brain damage to the frontal lobes, temporal regions, and limbic system. Other cognitive dysfunctions, such as memory problems and difficulty with the perception of consensual reality, are also likely to be present, complicating any psychiatric or psychological treatment applied.

Prosopagnosia

The immediate, automatic ability to recognize human faces—or even to identify the arrangement of eyes, nose, and mouth as a face—undergirds some very basic human social functions, such as the relationship between infants and their caregivers. Studies have found that newborn babies exhibit “face detection” skills practically from the moment of birth and that their ability to recognize individual faces—measured by the way they show a preference for the face of their primary caregiver—begins to develop only a few weeks later.

But in some cases, the ability to recognize faces may fail to come into being, due to an inherited developmental difference; otherwise, it can be stripped away by an injury to the brain. In either case, the condition is known as prosopagnosia, a term originating in the Greek words for face and not knowing. People with prosopagnosia can identify all the individual parts of a face but cannot meaningfully perceive the whole. To them, all faces generally look the same.

This may cause difficulty with reading others’ emotions or identifying people by age or gender. Fictional characters in the movies and on TV may all look alike to someone with prosopagnosia, who might also confuse other things with similar parts, like cars. This disorder can lead to problems in their social lives or with professional relationships—two spheres of relating in which forming strong connections is essential—and from there, can progress further into social anxiety or depression.

Pica

We’ve all met people who swear by unusual diets or consume unappealing foods for their own personal reasons. People with the disorder known as pica go even further, as they habitually swallow items that aren’t actually food—items such as bricks, stone, paper, cloth, or chalk.

This disorder is seen most commonly in children and is often harmless, depending on which non-food item is ingested. (Children younger than two years old often consume non-food items as a form of experimental engagement with the world; pica, therefore, is only diagnosed in people who are two years old or older. Pica is a somewhat less rare diagnosis in pregnant women, as well as in people with autism spectrum disorders or schizophrenia.)

Other commonly ingested materials, according to the National Institutes of Health, include dirt (a behavior called geophagy), raw starches like flour (amylophagy), ice (pagophagia), charcoal, ash, coffee grounds, or even eggshells. As you can imagine, eating these materials can cause physical harm to the body.

Treatment for pica, for children, often involves strategies designed to reinforce other, more healthy behaviors. It can also be treated by restricting a patient’s ability to come into contact with the substance they ingest or replacing it with another material that has similar physical properties but is less likely to be harmful.

These are only a few of the unusual psychological effects and disorders that social media has left largely unexplored. Remember, though, when you think of the conditions I’ve mentioned, that people with Capgras delusions, pica, prosopagnosia, or Charles Bonnet syndrome may have to work through challenging, difficult experiences just as other people are afflicted by more common disorders like depression or anxiety.

The symptoms I’ve mentioned may seem exotic, but they cause a great deal of confusion and suffering for those who must live with them. While the world of psychology is broader than social media may make it seem, the individuals who experience the least common conditions known to science are still just human beings like you and me.

Facebook/LinkedIn image: fizkes/Shutterstock

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