5 Rare Mental Disorders You Probably Haven’t Heard Of

Posted October 28, 2016 | By Tricia Hussung

Medical scan of human brain with title overlay

Mental health conditions affect millions of Americans. In fact, according to the National Alliance on Mental Illness (NAMI), approximately one in five adults in the United States experiences mental illness each year. Almost 7 percent of American adults had at least one major depressive episode in the past year, and more than 18 percent experienced an anxiety disorder. In addition, more than 1 percent of adults in the United States live with schizophrenia and around 2.6 percent live with bipolar disorder. Disorders like these are relatively well-understood, with clinicians and other mental health professionals utilizing a set of common diagnoses to come up with a differential diagnosis and treatment plan, Medscape says. However, some conditions are so rare that mental health professionals may never encounter them in their careers.

These uncommon conditions may be “merely a specific form of a more general psychopathology” and “span delusional misinterpretations; trauma-induced mental phenomena that range from anxiety to dissociative phenomena and psychosis; reactions to overwhelming experiences; and distinct phenomena following neurologic damage,” Medscape says. The following are examples of rare mental disorders.

Rare Mental Disorders

Stendhal Syndrome

Those with Stendhal syndrome experience physical and emotional anxiety as well as panic attacks, dissociative experiences, confusion and hallucinations when exposed to art. These symptoms are usually triggered by “art that is perceived as particularly beautiful or when the individual is exposed to large quantities of art that are concentrated in a single place,” such as a museum or gallery, Medscape says. However, individuals may experience similar reactions to beauty in nature. This syndrome is named after a 19th-century French author who experienced the symptoms during a trip to Florence in 1817. Stendhal syndrome may also be called hyperculturemia or Florence syndrome.


Also known as body integrity identity disorder, apotemnophilia is characterized by the “overwhelming desire to amputate healthy parts of [the] body,” according to Medscape. Though not much is known about it, this disorder is believed to be neurological. Those affected may attempt to amputate their own limbs or damage the limb so that surgical amputation is necessary. Apotemnophilia may be related to right parietal lobe damage in the brain. The condition is challenging to treat because people experiencing it often do not seek treatment. However, both cognitive behavioral therapy and aversion therapies can be attempted in order to treat apotemnophilia once treatment is sought.

Alien Hand Syndrome

This syndrome is characterized by the belief that one’s hand “does not belong to oneself, but that it has its own life,” Medscape says. Individuals experiencing alien hand syndrome have normal sensation but feel their hand is autonomous, with a “will of its own.” Those with alien hand syndrome may personify the limb as a separate entity: the unaffected hand is under the individual’s control while the affected hand has its own agenda. This syndrome may occur in individuals who have damage to the corpus callosum, which connects the two cerebral hemispheres of the brain. Other causes include stroke and damage to the parietal lobe. The hands then appear to be in “intermanual conflict” or “ideomotor apraxia,” meaning they act in opposition to one another.

Capgras Syndrome

This syndrome is named for Joseph Capgras, a French psychiatrist who explored the illusion of doubles. Those with Capgras syndrome hold the delusional belief that someone in their life, usually a spouse, close friend or family member, has been replaced by an impostor. It can occur in patients with schizophrenia, dementia, epilepsy and after traumatic brain injury. Treatment approaches mirror those utilized for the underlying disorders and often include antipsychotic medications.

Alice in Wonderland Syndrome

Also known as Todd syndrome, Alice in Wonderland syndrome (AIWS) is a neurologic condition “in which a patient’s sense of body image, space, and/or time [is] distorted,” according to Medscape. Those experiencing AIWS may have hallucinations, sensory distortion and an altered sense of velocity. AIWS results from change in perception. Though there are many symptoms, the most prevalent one is altered body image: Patients are confused about the size and shape of parts of their bodies. These symptoms can trigger panic and fear responses. AIWS is often associated with frequent migraines, brain tumors or drug use. It can affect children between the ages of 5 and 10.

As the stigma surrounding mental illness lessens (90 percent of Americans now value mental and physical health equally), more people are able to access the interventions and health care services they need. This in turn could lead to a clearer grasp of rare mental disorders like those covered here. If more trained mental health professionals are able to study syndromes like these, there is greater likelihood of identifying effective treatments and fostering greater understanding.

If you are interested in learning about mental disorders and other relevant topics in psychology like those covered here, consider Concordia University, St. Paul’s online Bachelor of Arts in Psychology. This program equips students with the knowledge and tools necessary to excel in the field of psychology, whether through entry-level careers or graduate study.