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

The individual experiencing erotomania is convinced that a person, usually someone of celebrity status, has fallen deeply in love with them. Even if the other person denies any feelings, the individual afflicted will not be convinced.

3. Cotard’s syndrome

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 exist.

4. 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.

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illnesses, Capgras delusion is a frightening disorder where the sufferer thinks that a close personal friend has been replaced by an imposter who looks exactly like their friend but is not them.

6. 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.

7. Synesthesia

Synesthesia is a neurological condition in which one stimulation of one sense can trigger an automatic reaction in another. This is how some people can see numbers as colours, smell certain words, or taste flavours in inanimate objects.

8. 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.

9. 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.

10. Boanthropy

An odd delusion here where the sufferer believes he or she is a cow or an ox and starts behaving as such. The disorder usually starts as a dream and then goes onto become a full-blown disorder. According to the Book of David, Nebuchadnezzar, King of the Neo-Babylonian Empire, may have suffered from the condition, as it states he was: “was driven from men, and did eat grass as oxen.”

11. 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.

12. Taijin Kyofusho

This is most common within Japanese culture and signifies a crushing fear of social interactions. It is not surprising that the Japanese suffer as they place much importance on social ritual and etiquette in social settings. The fear is that a sufferer will embarrass themselves or their hosts.

13. Ekbom’s syndrome

In Ekbom’s syndrome, 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.

14. Apotemnophilia

One of the most terrible mental illnesses where the person suffering has an overwhelming desire to amputate one of their healthy limbs. Also known as Body Integrity Identity Disorder (BIID) or Amputee Identity Disorder, 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

This is where your hand literally has a mind of its own and will not do what you want it to do. It grabs things, moves on its own accord, basically it’s as if it belongs to another person.

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. 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.

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.


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