Rare and Unusual Neuropsychiatric and Psychiatric Syndromes

Rare and Unusual Neuropsychiatric and Psychiatric Syndromes exist in the medical literature. Here are some of the more common ones to be aware of, especially during a medical and psychiatric assessment. Some external videos are also included on this page to help you better understand them (both humorous and educational ones).

Charles Bonnet Syndrome (CBS) is a common condition among people with serious vision loss characterized by temporary visual hallucinations. CBS is not due to a psychiatric condition, symptom of dementia, or other any other disease.[1] Rather, it is a condition specifically related to pathological vision loss. This is more common in individuals with macular degeneration, glaucoma, and diabetic retinopathy. Although it can be common, awareness is limited, which can cause confusion and concern among those experiencing and diagnosing it. There is no treatment, but symptoms usually resolve within 12-18 months. Patients can be reassured that this is a normal symptom to have that will self-resolve.[2]

Video 1: Charles Bonnet Syndrome (CBS) | Bee's story

Lilliputian Hallucinations

“Little people” - or also known as Lilliputian visions or hallucinations - are not uncommon in Charles Bonnet Syndrome.[3] The term “Lilliputian” is taken from the famous children's story, Gulliver's Travels, about Gulliver’s arrival at the land of Lilliput which is populated by tiny people. In 1909, Dr. Raoul Leroy introduced the term to medical literature noting that Lilliputian hallucinations depicts seeing people, animals and objects of greatly reduced size. He noted such visions have been reported for aeons and that its medical causes are varied. Many living with CBS report “seeing” miniature people who are about the size of a finger. Such tiny people can be “seen” directing a miniature horse-drawn carriage or driving a matchbox-sized vehicle. Sometimes, they are reported as being brightly costumed. Commonly, they comprise a mass procession like rows of a marching musical band or a phalanx of soldiers. These scenes tend to move across the person's visual field of view.
Further Reading

Fregoli Syndrome (or delusion) is the delusional belief that a familiar person (usually a “persecutor”) is following the patient, and repeatedly change their appearance and appear in the person's life.[4] When interacting with strangers, the individual may believe that strangers are in fact the “persecutor.”

This syndrome has often been discussed as a variant of the Capgras syndrome in the literature, but these two syndromes have different phenomenological structures and age and sex distributions. The condition is named after the Italian actor Leopoldo Fregoli, who was renowned for his ability to make quick changes in his appearance during his stage acts.

As in Capgras syndrome, Fregoli syndrome occurs most often in patients with schizophrenia, although it has also been reported in patients with dementia or epilepsy and after traumatic brain injury. Again, the management does not differ from the treatment of the underlying disorders, and usually involves antipsychotic medications, although in cases of dementia cognitive-enhancing treatments and nonpharmacologic approaches that diminish disorganization should be used. Aggression can be a risk from this delusion.[5]

Video: "The Fregoli Delusion" (Anomalisa, 2015)
Further Reading

Capgras Delusions, named after a French psychiatrist who described the illusion of doubles, is a delusion of misidentification. A person will have a delusional belief that an acquaintance, usually a spouse or other close family member, has been replaced by an identical looking impostor. An example would be a patient who thinks their mother and father have each been replaced by an imposter.

Capgras delusions occur most often in patients with schizophrenia, although it has also been reported in patients with dementia or epilepsy and after traumatic brain injury. Capgras delusion is thought to be due to disruptions/lesions of right hemisphere (temporo-parieto-occipital region) to the limbic system, so the visual-facial processing connections are most impaired.[6] Thus, non-visual stimuli might be less susceptible to these delusional beliefs

The management does not differ from the treatment of the underlying disorders, and may involves antipsychotic medications, although in dementia patients, cognitive enhancing treatments, and non-pharmacologic strategies that diminish the delusions (e.g. - non-visual forms of communication such as: family members recording reassuring voice messages, leaving letters/notes in their handwriting around the house, or speaking with the individual over the phone) should be used.

About 25% of Capgras cases may have some underlying neurological contribution and this likelihood only increases with age.[7]

Reduplicative Paramnesia

Reduplicative paramnesia consists of the delusional belief that a place or location has been duplicated, in that it exists in 2 or more places simultaneously, or that it has been 'relocated' to another site. It is basically the delusion of doubles of the Capgras syndrome, only that is does not refer to a person but to a place. “Reduplicative paramnesia” was first used by neurologist Arnold Pick in 1903 to describe a condition in a patient with suspected Alzheimer disease.
Video: Patient with Capgras delusion after a traumatic brain injury Video: Scrubs, Season 8, Episode 13 - Patient with Capgras delusion

What is the difference between Fregoli and Capgras?

Fregoli and Capgras delusions sound similar but are different!
  • In Fregoli delusions, the patient believes that there is a single individual (usually a persecutor) is masquerading as several other people, whose appearances he or she assumes at different times.
  • In Capgras delusions, the patient believes that their close family members or loved ones have each been replaced with an impostor.
  • The difference is that in Fregoli delusions, the patient believes that there is one person who is impersonating and appearing as multiple people in their life (including people who the patient may not be close to, e.g. - “This man who is after me is pretending to be a cashier at the grocery store, and now he is pretending to be the doctor and nurse.”). Compare this to Capgras, where it usually involves someone that the patient is emotionally connected with (e.g. - “My mother has been replaced with an imposter”).
  • As a summary:
    • Capgras involves family members
    • Fregoli involves strangers
Further Reading

Cotard Delusion is a specific nihilistic delusion named after Jules Cotard, a French neurologist, who first described the condition, which he called le délire de négation (negation delirium), in 1880. The affected person holds the delusional belief that he or she is already dead, does not exist, is putrefying or has lost his or her blood or internal organs.

It is most frequently observed in patients with psychotic depression or schizophrenias and is managed by focusing on the treatment of the underlying disorder. It can also secondary to a traumatic brain injury.

Video: Man With 'Walking Corpse Syndrome' Thought He Was Dead Video: Scrubs - Patient with Cotard Syndrome

Alice in Wonderland syndrome (AIWS) (or Todd syndrome) is a neurologic condition in which a patient's sense of body image, space, and/or time are distorted. Sufferers may experience micropsia or Lilliputian hallucinations, macropsia, or other sensorial distortions, including altered sense of velocity. AIWS is a result of change in perception as opposed to the eyes themselves malfunctioning. The most prominent and often most disturbing symptom is that of altered body image: the sufferer will find that he is confused as to the size and shape of parts of (or all of) his/her body.

These symptoms can be alarming, causing fear, even panic. Distortions can recur several times a day and may take some time to abate. AIWS is often associated with migraines, brain tumors, or the use of psychoactive drugs, and can also present as the initial sign of the Epstein-Barr virus or other infection. Rest is the best treatment. If associated with migraines, treatment is the same as that for other migraine prophylaxis, including anticonvulsants, antidepressants, beta blockers, and calcium channel blockers, together with strict adherence to the migraine diet.

Further Reading

Alien Hand Syndrome is the misattribution and belief that one's hand does not belong to oneself, but that it has its own life. The individual has normal sensation but believes that the hand, while still being a part of their body, is acting autonomously, having “a will of its own.” In effect, afflicted people lost the “sense of agency” associated with the purposeful movement of the limb while retaining a sense of “ownership” of the limb. Sufferers will often personify the alien limb, believing it to be “possessed” by some spirit or an entity that they may name or identify.

There is a clear distinction between the behaviours of the 2 hands in which the affected hand is viewed as “wayward” while the unaffected hand is under normal volitional control. At times, particularly in patients who have sustained damage to the corpus callosum that connects the 2 cerebral hemispheres, the hands appear to be acting in opposition to each other, which has been termed “intermanual conflict” or “ideomotor apraxia.”

Alien hand syndrome can be caused by stroke or neurodegenerative disorders including corticobasal degeneration. This includes areas of the corpus callosum, or frontal or parietal lobes.