Most people are familiar with psychiatric disorders such as schizophrenia and bipolar disorder, but some conditions are so rare that many psychiatrists will never come across a single case in their professional lives. Here Mark Griffiths of Nottingham Trent University presents five of the rarest – and strangest – syndromes known to psychiatry:
1. Fregoli syndrome
Fregoli syndrome is where someone believes that different people are actually the same person just changing their appearance. People with this syndrome are often persecuted by those they believe to be in disguise. The disorder is named after Leopoldo Fregoli, an Italian theater actor who was known for his remarkable ability to quickly change his appearance on stage. Fregoli syndrome usually occurs with other mental disorders, such as bipolar disorder, schizophrenia, and obsessive-compulsive disorder. It can also be caused by brain injury and by the use of the drug levodopa in the treatment of Parkinson’s disease.
A review in 2018 found that fewer than 50 cases have been reported worldwide since the condition was first described. However, a more recent study (2020) reported an incidence of 1.1% in patients after stroke, so definitely cases over 50 but still very rare. There is no known cure for Fragoli syndrome, but treatment with antipsychotic medications may reduce symptoms.
Cotard syndrome
Cotard’s syndrome, also known as ‘walking corpse syndrome’, is where people hold the delusional belief that they are dead and do not exist. Others believe that body parts are missing. The syndrome is named after Jules Coutard, a 19th-century French neurologist who first described the condition in 1882. Schizophrenia, depression, and bipolar disorder are risk factors for Coutard syndrome. However, it has also been reported as a rare side effect of the anti-viral drug acyclovir. The syndrome is believed to result from a disconnection between areas of the brain that recognize faces and areas that associate emotional content with facial recognition. This rare condition is usually treated with antidepressants, antipsychotics, and mood stabilizers, as well as electroconvulsive therapy.
3. Alien Hand Syndrome
Alien hand syndrome is one of the strangest neurological disorders. This is where a person’s hand appears to have a mind of its own and acts autonomously, and where the person feels that his or her hand does not belong to him. The syndrome was first identified in 1908 but was not clearly defined until the early 1970s. The term ‘alien hand syndrome’ was coined by Joseph Bogen, an American neurophysiologist, to describe the curious wayward behavior sometimes observed during recovery from certain types of brain surgery. People with alien hand syndrome usually have sensory processing disorders and dissociate themselves from the actions of their hands. Research indicates that people with the syndrome often recognize an alien hand, and may believe it is possessed by another spirit or alien life form.
Causes of the syndrome include dementia, stroke, prion disease (a fatal brain disease), tumors, and seizures.
Cases of alien hand syndrome have also been reported in patients who have had surgery to separate the left and right cerebral hemispheres for the treatment of severe epilepsy. The syndrome is extremely rare. A review in 2013 found just 150 cases in medical journals. Although there is no cure for alien hand syndrome, symptoms can be reduced and managed to some extent by keeping the affected hand occupied and involved in a task – for example, by clenching it into a fist. By giving an object for Other treatments include injections of botulinum toxin and mirror box therapy (see video). Stroke patients appear to have the best treatment success.
4. Ekbom syndrome
Ekbom’s syndrome is a tactile hallucination in which sufferers believe they are infested with parasites—often experienced as insects crawling under their skin. The syndrome is named after Swedish neurologist Carl Ekbom, who first described the condition in the late 1930s. The exact number of people with this syndrome is unknown, but one study reported about 20 new cases a year in a large US referral clinic. According to a meta-analysis of 1,223 Ekbom cases, the syndrome is more common in women (two-thirds of women, one-third of men), and more common in people over the age of 40. Symptoms usually last for three to four years.
Ekbom’s syndrome is associated with a number of conditions, including paranoid schizophrenia, organic brain disease, neurosis, and paranoid personality disorder. Alcohol withdrawal, cocaine abuse, stroke, dementia, and lesions in a part of the brain called the thalamus have also been reported in some people. Psychological treatment is often not sought by Ekbom’s syndrome sufferers, as they are convinced that the problem requires medical treatment.
5. Alice in Wonderland Syndrome
Alice in Wonderland syndrome, also known as Todd syndrome, refers to when a person’s body image, vision, hearing, touch, and sense of space/time are distorted. People with this condition usually perceive objects to be smaller than they actually are, while people seem larger than they are. Or vice versa: objects are perceived as larger than they are and people appear smaller. These experiences may be accompanied by feelings of paranoia.
Little is known about how common this disorder is. The victims are mostly children and migraine sufferers. People with the condition can be fearful and panic-stricken, so successful treatment often involves rest and relaxation. In most cases, this is a relatively short-term condition. The most recent review on Alice in Wonderland syndrome reports that about half of all sufferers are treated successfully.