We’ve all heard of depression and anxiety, but when it comes to obscure mental illnesses, we’re not so well-informed.

The human mind is relatively unchartered territory, and incredibly complex, but despite this, psychiatrists have managed to catalogue some pretty unusual and unexpected mental illnesses.

Here are just twenty of them:

1. Alice-in-Wonderland syndrome

Yes, this is a thing. It takes its name from the novel by Lewis Carroll and sufferers have a problem with perception, specifically that they cannot judge the size of certain objects. They might see some larger than they really are whilst others may seem smaller.

2. Erotomania

Sufferers of erotomania are convinced that someone is in love with them. The individual experiencing erotomania believes that a person, usually someone of a much higher social status (typically, celebrity status), has fallen deeply in love with them.

Even if the other person denies any feelings, the individual afflicted will not be convinced. That’s why dealing with this disorder is very difficult. There is nothing that can convince the delusional individual otherwise.

3. Celebriphilia

Similar to erotomania, celebriphilia involves an imaginary affair with a celebrity, but the other way round.

We’ve all had a celebrity crush at some point in our lives. But those with celebriphilia have more than a passing desire. They suffer from an overwhelmingly obsessive sexual desire for a celebrity. They can have romantic or purely erotic feelings. But the condition is all-consuming.

4. Cotard’s syndrome

First described in 1880 by French neurologist Jules Cotard, a very frightening but real syndrome in which the person suffering believes they are dead. Also called the ‘Walking Corpse Syndrome’, those suffering from Cotard’s are very hard to treat as they do not believe they are real, living beings.

Humans have a morbid curiosity when it comes to zombies and the undead. To the point where we can even suffer from a kind of zombie hell ourselves. Sufferers believe they are the walking dead. People with Cotard Delusion think their bodies are rotting and decomposing. Some are sure that they have lost a part of the body or an internal organ.

In severe cases, a patient may believe that he or she does not exist! The walking corpse syndrome usually results from a severe brain injury or mental disorder. Some are so convinced they are dead that they do not bother to eat or get up and eventually die. Luckily, this is probably one of our extremely rare mental disorders.

5. Lima Syndrome

Most of us have heard of Stockholm Syndrome, where the hostage becomes attached to their kidnapper, this is the opposite. The ones who have kidnapped become emotionally attached to their victim.

6. Capgras delusion

Probably one of the weirdest mental illnesses, Capgras delusion is a frightening disorder where the sufferer thinks that a close personal friend has been replaced by an imposter who looks exactly like their friend but is not them.

7. Folie à deux

Folie à deux means ‘madness of two’ and describes a delusion that is shared by two people. There is usually a primary and secondary person in the shared delusion. The primary starts the delusional thinking and passes it onto the secondary.

8. Factitious Disorder

No one likes being ill, but those with Factitious Disorder actually obsess about it. They intentionally make themselves ill. They will create illnesses and symptoms and tell lies to cover up the fact they are well.

This might involve going to different doctors or hospitals to keep their façade going. They will go to extreme lengths to prove they are ill. Even undergoing painful tests in order to keep the ruse believable.

Now, this is one of those rare mental disorders you might have heard of before. And you’d be right. Munchausen syndrome is no longer used by healthcare professionals.

9. Thought insertion

A person suffering from thought insertion will believe that their own thoughts are not their own and are coming from another person. This could be a symptom of schizophrenia.

10. Paris syndrome

A particular syndrome that affects mostly Japanese tourists, Paris syndrome is where someone visits the city and is extremely disappointed in what they find. Symptoms include anxiety, hallucinations, and even feelings of persecution.

11. Fregoli Delusion

Similar to Capgras Delusion, Fregoli Delusion is a belief that a stranger is posing as someone they know and love.

As we said above, people with Capgras Delusion think their loved ones have been replaced by an imposter. However, those suffering from this delusion think the opposite. They believe a stranger is a friend or family member. They think these strangers are wearing sophisticated disguises to mislead them.

12. Othello syndrome

Not reciting the Shakespeare play over and over again, but a case of extreme jealousy, as the title character suffered from. Afflicted people have very obsessive and all-pervading thoughts that their partner is cheating and will stalk, check up on, and interrogate them.

13. Ekbom’s syndrome

People who have Ekbom syndrome think that their skin is infested with insects. Also known as delusional parasitosis, sufferers feel real itching and can scratch themselves to the point of bleeding.

Since the sufferer believes that their body has been infested with parasites, either bugs, lice, fleas, or worms, they may go to several doctors to try and get treatment and could present with self-inflicted wounds from scratching.

They will often bring in what they believe to be a sample of the insect that is under their skin to show a doctor. They call in pest control as they believe their house is infested.

This syndrome is extremely difficult to cure and a multi-disciplined approach is best. For instance, as they believe they have a physical condition, it is best to have a physician and a psychiatrist on-board.

14. Apotemnophilia

Ever wanted to cut off part of your body? No, me neither. But those with apotemnophilia have a pathological desire to amputate a healthy limb such as a leg or arm.

Known as ‘body integrity identity disorder’, sufferers are driven to remove parts of their bodies. The desire can be so strong that some sufferers actually attempt to remove or irreparably damage their own limbs so that surgery is necessary. If a person does not receive help to overcome this disorder, they can even amputate their own limbs.

15. Clinical lycanthropy

This syndrome is where a person thinks they are turning into an animal, and not just a wolf, all kinds of cases have been reported, from cats, birds, frogs, even bees.

16. Alien hand syndrome

The syndrome is described when one’s hand behaves as if it has its own mind and will not do what you want it to do. It moves on its own accord, grabs things, touches other people, and acts beyond the control of the person it belongs to.

Sufferers of the alien hand syndrome feel as if their hand belongs to someone else and they have lost control of it. In severe cases, patients reported real battles with their hands, saying they tried to strangle their owners in their sleep. This syndrome, like most others, is caused by damage to the brain. Fortunately, the symptoms are treatable.

17. Reduplicative paramnesia

A rare condition that is typically caused by some kind of brain damage. Here a person believes that a specific place or location has been moved. For instance, soldiers who have suffered head injuries reported believing they were being treated in their local town when in fact they were hundreds of miles away.

18. Subjective doubles syndrome

Sufferers believe they have a doppelgänger who looks exactly like them but acts completely differently. This person can be a family member or a stranger, but quite often the person suffering becomes enraged that the person has stolen their identity.

19. Stendhal Syndrome

Stendhal Syndrome is where an individual is completely overcome by beautiful objects or art in a very short space of time. The sufferer would have a raised heartbeat, sweaty palms, and feel dizzy and confused.

20. Autophagia

Autophagia is a condition where you literally eat yourself or parts of yourself as a result of impulsive biting and chewing. And if you think that you would never do that, one man started off by chewing his fingernails and ended up eating his own fingers. As with most disorders, this one can vary from very mild to life-threatening forms.

This list has probably made you question what mental illnesses actually are. Do you know any other delusions and syndromes that could be a good fit for this list? Share your thoughts in the comments below.


  1. Psychology Today
  2. MedScape

Copyright © 2012-2024 Learning Mind. All rights reserved. For permission to reprint, contact us.

power of misfits book banner desktop

Like what you are reading? Subscribe to our newsletter to make sure you don’t miss new thought-provoking articles!

This Post Has One Comment

  1. Jenny

    Have you read RETHINKING MADDNESS? I suggest you do.

Leave a Reply