Mental disorders are often diagnosed today , and according to experts, one in three people has or will have some form of mental disorder in their lifetime.

Some of these psychological disorders are well known, such as depressive disorder, anorexia, bipolar disorder or schizophrenia. However, there are other mental disorders and illnesses that are rare due to their low frequency of occurrence or their strange symptomatology .

The Rareest Mental Disorders

But… what are these atypical mental disorders? What bizarre psychopathologies can we find?

Here is a list of 26 very rare mental disorders:

1. Altrophagia or Pica

Some eating disorders are very popular (such as anorexia or bulimia), however, there are others that are unknown to most of the population. One of them is Altrophagia or Pica, characterized by the fact that the person with this psychological disorder has an uncontrollable desire to eat non-nutritive and inedible substances such as dirt or paint.

Although some children may engage in this behavior because they are unaware of the harmful consequences of these substances, Pica can occur at an advanced age. These substances, besides not containing any nutritional value, can seriously damage the health of the person who consumes them.

  • Learn more about this disorder: “Pica (Alotrophagia): causes, symptoms, and possible treatments”

2. Folie à trois

La Folie à Trois is a very rare psychotic disorder . If the Folie à Deux, in which two people share the delusion, is already rare, the Folie à Trois, in which three individuals share the psychotic break, is less common.

A well-known case of Folie à Trois involves three American sisters. Two of them moved into the same home and were neighbours of their other sister. The disorder arose suddenly when the sisters became close, as they spent a lot of time together.

The three sisters had strong religious beliefs and the little girl began to question how there could be different interpretations of the Bible. This idea developed in the minds of the three sisters, and they decided to go to a house that was not theirs to begin their work. The owners of the home, who were in the house at the time, would not let them in, so they called the police. When they arrived on the scene, they were assaulted by the three sisters.

3. Alien hand syndrome

Alien Hand Syndrome (also known as Strangelove’s Hand Syndrome or Dr. Strangelove’s Syndrome) is a rare neurological disorder in which the hand goes on its own and does what it wants. The person feels that the hand is not his or her own .

This syndrome should not be confused with Phantom Limb Syndrome, which is suffered by some people who have lost a limb. You can learn more about the latter condition in this article: “Phantom limb and mirror box therapy.”

4. Trichophagia

Trichophagia or Rapunzel’s Syndrome is another very rare eating disorder because of the infrequency with which it occurs . It consists of the person suffering from this condition having an irresistible desire to eat their own hair. This causes serious problems in the stomach, as the hair causes a blockage in the intestine. It usually occurs together with trichotillomania, which is the pathological urge to pull out one’s own hair.

5. Self-Cannibalism or Self-Arcophagy

This rare mental disorder is characterized by the person eating his or her own skin or consuming his or her own blood . Autocannibalism also occurs in Lesch-Nyhan syndrome, a disorder in which a person self-mutes and consumes his or her own body parts.

Individuals with this disease engage in compulsive behaviors such as biting their fingertips and lips (or any other body part they have access to), poking their fingers into their eyes, or throwing their body against a wall.

6. Boantropia

If it is already rare in Zoanthropy, where the person thinks it is an animal, in Boanthropy he thinks it is a cow or an ox . This type of behaviour is known as lycanthropic delirium, a psychopathological phenomenon that manifests itself as an unrealistic belief in one’s own transformation of the body into that of an animal. In this case, the person adopts the typical behaviours of the animal in question.

7. Aboulomania

It may be that sometimes we have to make a difficult decision and we don’t know what to do, which is not normal. On the other hand, there are people who suffer from aboulomania, that is, the inability to make decisions . Deciding what to eat in a restaurant when you have the menu in your hand becomes a difficult situation when a person suffers from this psychological disorder.

8. Foreign Accent Syndrome

Foreign Accent Syndrome is one of the rarest neurological disorders, usually resulting from brain injury, such as a stroke or cerebrovascular injury. It is a rare condition, which causes a person to speak their native language as if they had a foreign accent.

9. Hikikomori

Hikikomori is a psychopathological and sociological phenomenon that is characterized by the person’s isolation from society and closure in his room , avoiding contact with the people around him . It receives this name because, until recently, it was characteristic of Japan. Today we know that there are also cases in the West, even in Spain.

10. Diogenes Syndrome

Diogenes Syndrome is one of those rare and well-known disorders. It is characterized by people who suffer from this condition storing and collecting many belongings and possessions in their home . These people are unable to get rid of them, so they accumulate more and more waste and abandoned objects in general. People find it strange that a person can live surrounded by garbage and this generates isolation, as well as hygiene and food problems.

You can learn more about this disorder in our article: “Diogenes Syndrome: causes, symptoms and treatment”

11. Tourette’s syndrome

One of the most striking disorders is undoubtedly Tourette’s Syndrome or Gilles de Tourette Syndrome (by Georges Gilles de Tourette, who is the eponym for this disorder). It is a neurological disorder characterised by the fact that those who suffer from it make involuntary movements and sounds without a specific purpose .

To better illustrate what this disorder is, we invite you to learn more about a well-known real case. You can see it in this article that contains audiovisual content: “Super Taldo: the famous case of the Chilean child with Tourette’s Syndrome.”

12. Stockholm syndrome

This disorder occurs in those who have been kidnapped, show some kind of positive feeling towards their captors and create emotional ties with them . Some experts think it is a defence mechanism, a reaction provoked by the stress of a traumatic situation that has occurred. It is considered a rare disorder because it is difficult to understand.

  • You may be interested in: “Stockholm Syndrome: Friend of my kidnapper”

13. Taijin Kyofusho Syndrome

Taijin Kyofusho Syndrome is a social anxiety disorder (SAD) that commonly occurs in Japan, and is characterized by a strong fear that the body, its parts or its functions will be offensive to other people .

It can be confused with social phobia, but while the latter refers to the fear of being embarrassed in front of others, individuals suffering from Taijin Kyofusho Syndrome are afraid of embarrassing others by virtue of their presence or appearance.

In other words, in social phobia a person worries about his reaction, in Taijin Kyofusho he worries about how others will feel about his presence.

14. Erotomania

This mental disorder is rare. The person who suffers it has the illusory belief that an individual, of superior status, is in love with him or her, with the peculiarity that the person supposedly in love is usually someone famous . A strange and unusual pathology.

15. Omphalophobia

Omphalophobia is the irrational fear of navels . This fear or discomfort is towards your own navel or that of others. These individuals experience difficulties when bathing because they cannot look at or touch their navel.

The symptoms are those characteristic of any specific phobia: irritability, nausea, dizziness, vomiting, feeling of anger along with rage, as well as a feeling of total helplessness. Without doubt, one of the rarest mental disorders.

16. Jerusalem Syndrome

A disorder is strange that manifests itself in the form of delusions, visions and loss of contact with reality, after visiting the Holy City of Jerusalem or other sacred areas of Israel . It is a psychotic disorder that affects both tourists and people living in this city.

17. Paris syndrome

Jerusalem is not the only city on this list of mental disorders, for we can also find the city of light: Paris. The Paris Syndrome is a psychological condition experienced by Japanese tourists who are very disappointed when visiting the French capital . The reason seems to lie in the unrealistic expectations that Japanese people have of this metropolis.

  • You can learn more in our article: “Paris Syndrome: the strange disorder some Japanese tourists suffer from”

18. Koro Syndrome (Genital Restriction Syndrome)

Another disorder that occurs more frequently in Asian countries is Koro Syndrome, an anxiety disorder characterized by the person suffering from it thinking that his penis is shrinking every day until it disappears. Not only that, but his member is absorbed by the body until it causes him to die.

Although it occurs mostly in men, some women also believe that their external genitals and nipples will be absorbed into the body and die.

19. Alice in Wonderland Disease

Alice in Wonderland Disease is characterized by the presence of micropsy or macropsy, and is a neurological disorder affecting visual perception in which the person sees objects around him as smaller (micropsy) and larger (macropsy) . Patients also suffer from an alteration in time perception in certain places or moments

20. Münchausen syndrome

Münchausen syndrome is a type of factitious disorder. It is a condition in which people constantly and intentionally simulate very striking illnesses. This can cause the person to self-harm or eat toxic substances in order to receive care . Their motivation is to assume the role of the sick person and to be cared for.

21. Triscaidecaphobia

This phobic disorder is due to irrational fear of the number 13 . People with this phobia avoid this number because of the tremendous anxiety they feel when seeing or touching anything that contains it. This type of anxiety disorder can be distinguished from parascevedecatryaphobia, which is the phobia of Friday the 13th.

22. Crystal illusion

This is a very rare psychological disorder in which the person believes that his body is made of glass and that it can break at any time . Despite the evidence that they are made of flesh and blood, they are not able to abandon this false belief.

23. Cotard’s syndrome

This serious mental disorder is rare. It is characterized by the subject’s perception of being separated from reality. He can see his body in the mirror, but he notices it as something strange, as if it didn’t exist. Individuals with Cotard’s Syndrome, often believe they are dead or in a state of decomposition .

  • Related text: “Cotard’s Syndrome”: living people who think they are dead”

24. Fregoli syndrome

An unusual mental disorder in which the person suffering from it has the belief that different people are, in fact, one . Therefore, he thinks that this individual is capable of modifying his physical appearance. It is often accompanied by persecutory delusions.

25. Capgras syndrome

If the previous point seemed strange to you, even stranger is Capgras Syndrome. People who suffer from it think that their friends and family are in fact impostors , despite the fact that there are no objective reasons for this belief. They tend to react with hostility towards their family and friends, thinking that they are not them.

26. Reduplicative Paramnesia

This type of delusional disorder is really curious, because the person has the delusional idea that the context or scenario in which he or she is in has been duplicated , that is, there is another one or several identical ones somewhere in the world. They may also believe that that specific place has been moved to another location.