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Double trouble: Syndrome of subjective doubles‬

In a previous blog on Delusional Misidentification Syndromes, I briefly mentioned the rare syndrome of ‘subjective doubles’ (SSD). Also known as Christodoulou syndrome (after the Greek psychiatrist Dr. George Nikos Christodoulou who first wrote about the syndrome), SSD 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 but that have part or sometimes all of the SDD sufferer’s personality. If the sufferer believes that (some or all of) their personality has been transferred to their doppelganger, they may also experience depersonalization (i.e., a problem of self-awareness in which individuals feel they have little control over social situations and feel they are watching themselves act in a vague and dreamlike state. 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. The Wikipedia entry on SSD cited the case of a man who became depersonalized after an operation and was convinced his brain had been placed into someone else’s head and then claimed he recognized the other person.

In the original paper on SSD in a 1978 issue of the American Journal of Psychiatry, Dr. Christodoulou described the case of a young 18-year-old woman who claimed that a female neighbour had (via an “elaborate transformation” involving “metapmophosis”) acquired all of her physical characteristics (“same face, same build, same clothes, same everything’) and become an identical double. To become her double, the female case study believed her doppelganger had used a mask, wig, and special makeup. Her female neighbour wasn’t the only doppelganger as the woman also claimed at least one other woman had become her doppelganger. In rare instances, there may be comorbidity with the Capgras delusion (another misidentification syndrome) and is then referred to ‘subjective Capgras syndrome’. In fact, there are a number of different sub-types of SDD. As the online Dictionary of Hallucinations notes:

A subdivision of the syndrome of subjective doubles yields a ‘Capgras type’ (characterized by the delusional conviction that unseen doubles are active in the affected individual’s environment), an ‘autoscopic type’ (in which doubles of the self are perceived, ‘projected’ onto other people or objects, as in pareidolia), and a ‘reverse type’ (in which the affected individual believes to be an impostor or to be about to be replaced by someone else). The syndrome of subjective doubles is associated with various psychiatric disorders (notably the group of so-called schizophrenia spectrum disorders) and neurological disorders (notably disorders of the right parieto-temporal lobe). Conceptually and phenomenologically, the syndrome of subjective doubles constitutes the counterpart of a syndrome called ‘mirrored self-misidentification’, in which the affected individual is unable to identify his or her mirror image as oneself”.

Although most sources cite Dr. Christodoulou’s paper in the American Journal of Psychiatry as the first recorded case of SSD, he actually published a paper a year earlier in a 1977 issue of Acta Psychiatrica Belgica on the treatment of the syndrome of doubles. In this paper, Christodoulou used biological methods to treat 20 psychiatric patients with SDD or the related syndromes (Frégoli, intermetamorphosis, Capgras) aged 17 to 67 years of age. His patients were treated with ECT, antidepressants, neuroleptics, and antiepileptics (in some cases given singly whereas others were in combination). It was reported that:

“Results show that (a) the syndrome of doubles responded to various biological treatment methods; (b) in depression, it responded to tricyclic antidepressants; (c) in schizophrenia or organic psychosis, it usually responded to neurolytics; (d) in schizophrenia, it had more chances of responding to trifluoperazine given alone or in association with other psychopharmacological drugs; and (e) in certain cases, combination of antipsychotic treatment with treatment of coexisting organic dysfunctions appeared to be important”.

In another 1978 paper (in the Journal of Nervous and Mental Disease), Dr. Christodoulou described the course and prognosis of 20 patients with the syndrome of doubles (including Capgras syndrome, Fregoli syndrome, intermetamorphosis syndrome, and SDD – and presumably the same cases reported in the 1977 paper). He reported that the onset of the syndromes occurred either synchronously or at a later stage than the onset of the associated psychosis. In seven of the 20 cases, the syndrome failed to remit. In the remaining 13 cases, remission occurred either synchronously with or later than the remission of the basic psychosis. In all cases where there was comorbid depression, the syndromes cleared shortly after the successful treatment of the depressive illness. It was also noted that relapse of the basic psychotic condition in the setting of which the syndrome had originally developed was usually accompanied by the syndrome reappearing. In one of his most recent papers (from a 2009 issue of Current Psychiatry Reports), Christodoulou and three of his colleagues noted that:

“The delusional misidentification syndromes [including SDD] are rare psychopathologic phenomena that occur primarily in the setting of schizophrenic illness, affective disorder, and organic illness. They are grouped together because they often co-occur and interchange, and their basic theme is the concept of the double. They are distinguished as hypoidentifications (Capgras’ syndrome) and hyperidentifications (the other three syndromes [including SDD]).,,[We] propose that the appearance of these syndromes must alert physicians to investigate the existence of possible organic contributions”.

Compared to other misidentification syndromes, SDD appears to be relatively rare and is often comorbid with other similar conditions. For instance, in a 1986 issue of the Journal of Clinical Psychiatry, Dr. A.B. Joseph described the case of a 30-year old white male who had SDD along with paranoid schizophrenia, Cotard’s syndrome, Capgras delusion, and palinopsia (visual perseveration). Joseph concluded that cerebral dysfunctions in the confluence of the parietal, temporal, and occipital regions of the brain appeared to account for the disorders. Similarly, a 1996 paper in the journal Australasian Psychiatry, Dr. S. Atwal and Dr. M. Khan reported an unusual case of Capgras syndrome coexisting with three related syndromes (Fregoli syndrome, intermetamorphosis syndrome, and SDD).

In a more recent 1991 paper in the journal Psychological Medicine, Dr. H. Forstl and his colleagues examined the psychiatric, neurological and medical aspects of 260 cases suffering misidentification syndromes. Among the sample SDD was relatively rare as 174 cases had a Capgras syndrome misidentifying other persons, 18 a Fregoli syndrome, 11 intermetamorphosis, 17 reduplicative paramnesia and the rest had other forms or combinations of mistaken identification (including SDD). The most common comorbid disorders among those who misidentified themselves or other were schizophrenia (n=127; mostly paranoid schizophrenia), affective disorder (n=29), and organic mental syndromes including dementia (n=46). The authors reported that:

“The misidentification of persons can be a manifestation of any organic or functional psychosis, but the misidentification of place is frequently associated with neurological diseases, predominantly of the right hemisphere. Misidentification syndromes show a great degree of overlap and do not represent distinctive syndromes nor can they be regarded as an expression of a particular disorder. These patients deserve special diagnostic and therapeutic attention because of the possible underlying disorders and their potentially dangerous behaviour”.

Finally, I thought I would leave you with a paper from a 2005 issue of the journal Psychopathology that reported some extreme cases involving delusional misidentification syndromes (DMS) and the danger associated with them. Dr. M. Aziz and his colleagues reported on three cases with histories of paranoid schizophrenia tall of who developed DMSs:

“Two of them acted out on delusional thinking toward their sons. Case 1 managed to kill her son and Case 2 was caught twice trying to choke him. Our case reports suggest that the degree of threat perceived by the patient from the delusionally misidentified object is the most important factor in determining the patient’s response to the delusions. Alcohol and substance intoxication facilitated the patients’ acting out on their delusions, but did not explain the genesis of the delusions. There is a need to continue to study patients with DMS in order to provide opportunity for greater understanding of the psychopathology of DMS”.

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

Further reading

Atwal, S., & Khan, M. H. (1986). Coexistence of Capgras and its related syndromes in a single patient. Australasian Psychiatry, 20, 496-498.

Aziz, M.A., Razik, G.N., & Donn, J.E. (2005). Dangerousness and management of delusional misidentification syndrome. Psychopathology, 38(2), 97-102.

Christodoulou, G.N. (1977). Treatment of the syndrome of doubles. Acta Psychiatrica Belgica, 77(2), 254-259.

Christodoulou, G.N. (1978). Syndrome of subjective doubles. American Journal of Psychiatry, 135, 249-251.

Christodoulou, G.N. (1978). Course and prognosis of the syndrome of doubles. Journal of Nervous and Mental Disease 166, 73-78.

Christodoulou, G.N., Margariti, M., Kontaxakis, V. P., & Christodoulou, N. G. (2009). The delusional misidentification syndromes: strange, fascinating, and instructive. Current Psychiatry Reports, 11(3), 185-189

Dictionary of Hallucinations (2013). Syndrome of subjective doubles. Located at:

Enoch, D., Ball, H. (2001). Uncommon Psychiatric Syndromes (Fourth Edition). London: John Wright & Sons.

Forstl, H.A.N.S., Almeida, O. P., Owen, A. M., Burns, A., & Howard, R. (1991). Psychiatric, neurological and medical aspects of misidentification syndromes: A review of 260 cases. Psychological Medicine, 21, 905-910.

Joseph, A.B. (1986). Cotard’s syndrome in a patient with coexistent Capgras’ syndrome, syndrome of subjective doubles, and palinopsia. Journal of Clinical Psychiatry, 47, 605-606.

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.