The brain is amazing. It is intensely complex, relies on a complicated scaffold of processes, involves constant communications over trillions of synapses, and it has to be both incredibly specialized and also able to handle all the new things we constantly throw at it. A healthy, functioning human brain is fascinating, but as humans, we like the weird stuff. Knowing how things work can be interesting, but knowing how things can break is more fun. For today's Brain Awareness Week post, I'm doing a rundown of the wacky-- the types of delusions that you mostly only see on TV.
Capgras Delusion- People with Capgras syndrome believe that someone close to them or important to them-- friend, spouse, parent, child, pet-- has been replaced with an identical imposter. Usually they only believe that one person is an imposter, not everyone around them, and it can be incredibly frustrating that no one else sees what you see. These patients don't necessarily know who the imposter is or why their loved one has been replaced, only that they have. Capgras is thought to be related to deficits in communication between areas of the brain, such as areas that specialize in recognizing faces and areas that process emotion or areas important for remembering specific events.
Cotard Delusion- In Cotard delusion, patients believe that they are dead, don't exist, don't have internal organs, or are rotting away. The most common manifestation is the denial of a person's own existance. Like Capgras delusion, it's thought to be related to disconnection between face recognition centers and structures known for their role in emotion processing. This disconnection is often due to brain degeneration, injury, or lesion.
Fregoli Delusion- In keeping with the dysfunctional face processing trend, Fregoli delusion is the belief that a single person is using disguises to appear as multiple different people in the patient's life, usually due to some sort of persecutory reason.
Syndrome of Subjective Doubles- Syndrome of subjective doubles is the belief that the person has a Doppelgänger out in the world, living their own life. Usually, the Doppelgänger has a separate personality and life history than the patient does, but sometimes it is also a mental clone. The Doppelgänger may be a different age, or the patient may believe that THEY are actually the Doppelgänger. Syndrome of subjective doubles is a delusion that is often present in schizophrenia and bipolar disorder.
Somatoparaphrenia- This mouthful describes the belief that an appendage or even one side of the body does not belong to the patient. They might believe that the limb is not attached to their body, or they be convinced someone else limb has been attached to them. Sometimes this is found in cases of hemineglect, and sometimes the patient will experience paralysis in that appendage. It is believed to be due to brain injury, degeneration, or lesion.
Clinical Lycanthropy- If you watch Supernatural, you'll already guess what this delusion is. Clinical lycanthropy is the belief that the person can transform into an animal. Like a werewolf, though it doesn't have to be a wolf. The patient either recalls feeling like an animal, or will engage in animal-like behavior: moving like the animal or making similar sounds. Clinical lycanthropy is a specific manifestation of other psychotic disorders like schizophrenia or bipolar disorder.
Folie a deux- French for "madness of two" (Note: you can also have folies of other numbers, or even groups). This is a shared delusion. It occurs either when one dominant person develops a delusion and is able to influence a secondary person to have the same delusion. The second person in this situation most likely would never have developed a delusion on their own, and their delusion will resolve on its own if the two are separated. The other form of folie a deux occurs when two people develop delusions independently that feed off of each other and fuel each other, merging into a single, shared delusion. This could be, for example, two people prone to paranoia and persecutory thoughts. One person notices something sketchy that confirms the other's suspicions, and now the first person has more evidence for their belief, and it snowballs from there.
These are all pretty freaking rare disorders and syndromes, much rarer than soap operas and crime procedurals would have you believe. They are all real, but they're often exploited for the sake of story line-- having someone with Capgras kill the person they think is an imposter, or someone with somatoparaphrenia cut off the offending limb with a table saw. The brain is amazing, but it does some really weird things.
Signing off til tomorrow, when I'll have a new crazy brain phenomenon to blow your .... mind (see what I did there? Get it? Because, like, mind-brain?) In the meantime, Twitter here, Facebook here. Follow, share, retweet.