Identity marred: A ‪beginner’s guide to Delusional Misidentification Syndrome‬s

Some of the strangest mental and neurological syndromes that exist involve delusional misidentification. There are many different types and they all come under the umbrella term Delusional Misidentification Syndrome (DMS)‬. It was Dr. Nikos Christodoulou who introduced the term in his 1986 edited collection The Delusional Misidentification Syndromes. All DMSs involve a belief by the affected individual that the identity of something (i.e., a person, place, object, etc.) has altered or changed in some way. There are many variants of DMS, and in most cases the delusion is monothematic (i.e., it only concerns one particular topic). Here is a brief summary of the different types:

The Fregoli delusion: This refers to an individual who has the belief that more than one person that they have met is the same person in more than one disguise. The disorder is named after Leopoldo Fregoli an Italian theatre actor who was known for his remarkable ability to quickly change his physical appearance while on stage. The first reported case was in 1927 (by Dr P. Courbon and Dr. G. Fail in a French psychiatry journal) when a female schizophrenic (aged 27 years) claimed that she was being persecuted by two actors that she had seen at the theatre. According to the woman the actors “pursued her closely, taking the form of people she knows or meets”. Compared to other forms of delusional misidentification, the Fregoli delusion is thought to be the least common.

The Capgras delusion: This refers to an individual who has the belief that someone (typically a spouse or close relative) has been replaced by an identical-looking imposter. The delusion was named in 1923 after a French psychiatrist (Dr. Joseph Capgras) reported the case of a French woman who believed that her husband (and some other people she knew) had been replaced by identical looking doubles. Females are slightly more likely than males to have the delusion (approximately 60% females and 40% males). The disorder is most likely to found in individuals that have a brain injury, schizophrenia and/or dementia, but has also been associated with other medical conditions including hypothyroidism, diabetes, and migraines. There was also a case study published in a 2010 issue of the journal Biological Psychiatry (by Dr. P.R. Corlett and colleagues) who reported that the delusion had been induced by a psychologically healthy following the taking of the drug ketamine.

Subjective doubles (aka Christodoulou syndrome): This refers to individuals who have the belief that there are (one or more) doubles of themselves (i.e., doppelgangers) that carry out actions and behaviours independently and lead a life of their own. The disorder was first identified by Dr. Nikos Christodoulou in a 1978 issue of the American Journal of Psychiatry. As with other DMSs, subjective doubles syndrome typically arises as a consequence of a mental disorder, brain injury (typically the right central hemisphere) or a neurological disorder. In rare instances, there may be comorbidity with the Capgras delusion and is then referred to ‘subjective Capgras syndrome’.

Intermetamorphosis: This refers to an individual who has the belief that people in their immediate vicinity change identities with each other but keep the same appearance. The disorder was first reported in 1932 by Dr. P. Courbon and Dr. J. Tusques (again in a French psychiatry journal), and again shares comorbidity with mental and/or neurological disorders. An interesting case study was published in a 2002 issue of the journal Cognitive Neuropsychiatry by Dr. M.F. Shanks and Dr. A. Venneri. They described a man with Alzheimer’s disease who mistook his wife for his dead mother and (at a later date) his sister. He later mistook his son for his brother and his daughter for another sister. As the delusion occurred when speaking on the telephone to these misidentified individuals he was not diagnosed with either visual agnosia (i.e., an inability of the brain to recognize or understand visual stimuli) or prosopagnosia (i.e., ‘face-blindness’ – the inability to recognize faces).

There are also some other conditions that could feasibly be classed as DMSs including (i) mirrored-self misidentification, (ii) reduplicative paramnesia, (iii) delusional companion syndrome, (iv) clonal pluralization of the self, and (v) the Cotard delusion (which I covered in a previous blog). Very briefly:

  • Mirrored-self misidentification: This refers to an individual who has the belief that when they look in the mirror they see someone else.
  • Reduplicative paramnesia: This refers to an individual who has the belief that something (e.g., a person, a body part, an object, or a place has been duplicated.
  • Delusional companion syndrome: This refers to an individual who has the belief that inanimate objects are actually alive.
  • Clonal pluralization of the self: This refers to individuals who have the belief that there are multiple copies of themselves (both physically and psychologically identical).
  • The Cotard delusion: This refers to an individual who has the belief that they are dead, don’t exist and/or immortal.

There are some cases reported where individuals have more than one DMS simultaneously. For instance, in very rare cases, a person may suffer from both the Fregoli delusion and the Capgras delusion at the same time. Such individuals often experience both depersonalization and derealization and typically co-occur with other mental disorders such as bipolar disorder, schizophrenia, obsessive-compulsive disorders, and/or other mood disorders. In general, DMS is thought to arise because of a dissociation between identification and recognition processes. The Wikipedia entry on the Fregoli delusion (which also examines other DMSs) concludes:

“The study of DMS currently remains controversial…Although there is a plethora of information on DMS, there are still many mysteries of the physiological and anatomical details of DMS. An accurate semiological analysis of higher visual anomalies and their corresponding topographic sites may help elucidate the aetiology of Fregoli’s and other misidentification disorders”.

Dr Mark Griffiths, Professor of Gambling Studies, International Gaming Research Unit, Nottingham Trent University, Nottingham, UK

Further reading

Christodoulou G.N. (1986). Delusional Misidentification Syndromes. Basel: Karger.

Christodoulou G.N. (1977). The syndrome of Capgras, British Journal of Psychiatry, 130, 556.

Christodoulou G.N. (1978). Syndrome of subjective doubles. American. Journal of Psychiatry, 135, 249.

Corlett, P.R., D’Souza, D.C. & Krystal, J.H. (2010). Capgras Syndrome induced by ketamine in a healthy subject. Biological Psychiatry, 68(1), e1–e2.

Ellis HD, Luauté JP, Retterstøl N (1994). “Delusional misidentification syndromes”. Psychopathology 27 (3-5): 117-120.

Benson DF, Gardner H, Meadows JC (February 1976). Reduplicative paramnesia. Neurology 26, 147-151.

Berrios G.E., Luque R. (1995). Cotard Syndrome: clinical analysis of 100 cases. Acta Psychiatrica Scandinavica 91, 185-188.

Shanks MF, Venneri A (2002). The emergence of delusional companions in Alzheimer’s disease: An unusual misidentification syndrome. Cognitive Neuropsychiatry, 7, 317-328.

Vörös, V., Tényi, T., Simon, M. & Trixler, M. (2003). Clonal pluralization of the self: A new form of delusional misidentification syndrome. Psychopathology 36, 46-48.

Sno, H.N. (1994). A continuum of misidentification symptoms. Psychopathology, 27, 144-147.

About drmarkgriffiths

Professor MARK GRIFFITHS, BSc, PhD, CPsychol, PGDipHE, FBPsS, FRSA, AcSS. Dr. Mark Griffiths is a Chartered Psychologist and Professor of Behavioural Addiction at the Nottingham Trent University, and Director of the International Gaming Research Unit. He is internationally known for his work into gambling and gaming addictions and has won many awards including the American 1994 John Rosecrance Research Prize for “outstanding scholarly contributions to the field of gambling research”, the 1998 European CELEJ Prize for best paper on gambling, the 2003 Canadian International Excellence Award for “outstanding contributions to the prevention of problem gambling and the practice of responsible gambling” and a North American 2006 Lifetime Achievement Award For Contributions To The Field Of Youth Gambling “in recognition of his dedication, leadership, and pioneering contributions to the field of youth gambling”. His most recent award is the 2013 Lifetime Research Award from the US National Council on Problem Gambling. He has published over 600 research papers, four books, over 130 book chapters, and over 1000 other articles. He has served on numerous national and international committees (e.g. BPS Council, BPS Social Psychology Section, Society for the Study of Gambling, Gamblers Anonymous General Services Board, National Council on Gambling etc.) and is a former National Chair of Gamcare. He also does a lot of freelance journalism and has appeared on over 2000 radio and television programmes since 1988. In 2004 he was awarded the Joseph Lister Prize for Social Sciences by the British Association for the Advancement of Science for being one of the UK’s “outstanding scientific communicators”. His awards also include the 2006 Excellence in the Teaching of Psychology Award by the British Psychological Society and the British Psychological Society Fellowship Award for “exceptional contributions to psychology”.

Posted on August 30, 2013, in Case Studies, Culture Bound Syndromes, Mania, Physiological disorders, Psychiatry, Psychological disorders, Psychology and tagged , , , , , , , , , , . Bookmark the permalink. Leave a comment.

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