3rournal ofNeurology, Neurosurgery, and Psychiatry 1995;58:499-501 499 SHORT REPORT J Neurol Neurosurg Psychiatry: first published as 10.1136/jnnp.58.4.499 on 1 April 1995. Downloaded from Shared delusions of doubles G N Christodoulou, M M Margariti, D E Malliaras, S Alevizou Abstract Folie a deux, on the other hand,6 is a rare This is the first report of two partners in phenomenon in which two closely associated a folie a deux situation manifesting iden- persons share the same delusions. Four sub- tical Capgras delusions. It is postulated types have been described. The most frequent that the Capgras syndrome developed as is folie imposee, in which one partner is a result of interaction between a domi- usually dominant and active and the other nant patient with primarily paranoid one is passive, submissive, and suggestible. psychopathology and a submissive one with primarily organic dysfunction. The submissive "neuro-organic" partner Case report experienced a non-delusional misidenti- The dominant partner was a 54 year old, fication that acquired a delusional com- obsessional, stubborn and touchy, but also ponent and developed into the Capgras sociable and warm widow, mother of two syndrome as a result of elaboration by children, with a family history of depression, the dominant paranoid partner, who who started being delusional in 1971, shortly subsequently "imposed" the Capgras after her husband's death, which she attrib- delusion on the submissive partner. The uted to poisoning. She continued to express submissive patient, and, to a lesser similar ideas, particularly in relation to her extent the dominant patient, had evi- neighbours and her relatives. dence of organic cerebral dysfunction. The submissive partner was her daughter, a pleasant, good looking, loyal, and obedient (7 Neurol Neurosurg Psychiatry 1995;58:499-50 1) law student of 24, with limited social inter- action. She was closely associated with and dependent on her mother. She became an Keywords: Capgras syndrome; delusions of doubles; active participant in her mother's misinterpre- http://jnnp.bmj.com/ folie a deux; organic dysfunction tative behaviour in 1988 when she started accusing her neighbours and misinterpreting Both the Capgras delusion (delusion of the behaviour of her grandmother and aunt, doubles) and folie a deux are rare conditions always in keeping with the beliefs of her and their combination is even more rare. In mother. fact, a shared Capgras delusion in the setting In 1989 she informed her mother that her of folie a deux has never been reported in the teacher in English had the ability to change medical literature. This occurrence provides her facial characteristics. Similarly, she on October 2, 2021 by guest. Protected copyright. the opportunity to study the step by step reci- reported that the characteristics of a girl at procal reinforcement of two partners (one of school kept changing ("at times her hair is them contributing her misinterpretative psy- short and at other times it is long"). She was chopathology, the other one her organicity) amused by these changes, by contrast with eventually to develop a shared Capgras delu- her mother who became very upset and made sion. Furthermore, it supports the view that her discontinue her English lessons and stop Athens University organic participation is important in the seeing the girl with the hair transformations. Departnent of Psychiatry, Eginition pathogenesis of the delusional misidentifica- Some months later, financial help was Hospital, Athens, tion syndromes. requested from the aunt but this was refused Greece The Capgras syndrome' is the delusional because of short notice. This produced G N Christodoulou negation of identity of a familiar person and further in the daughter's relation- M M Margariti aggravation D E Malliaras the conviction that this person has been ship with her aunt who complained to her S Alevizou replaced by a physically identical double. It is mother that she did not behave "like a real Correspondence to: a variant of the delusional misidentification relative". Professor G N Christodoulou, Department syndromes, the other three subtypes being the In June 1991 the mother's delusions of Psychiatry, University of syndrome of Fregoli, the syndrome of inter- became more pronounced. She accused her Athens, Eginition Hospital, 74, Vas Sofias Avenue, metamorphosis, and the syndrome of subjec- neighbours of stealing various objects and 11528 Athens, Greece. tive doubles.23 There is evidence that organic decided to sue them. The daughter, who Received 5 July 1994 factors play a major part in the pathogenesis sided with her mother, as always, was sent to and in revised form 3 October 1994 of these syndromes45 although all Capgras her aunt to ask her to appear in court as a Accepted 14 October 1994 cases cannot be explained on this basis. witness. On return, she stated that the aunt 500 Christodoulou, Margariti, Malliaras, Alevizou appeared physically "different". The mother 108, performance 72, mean 92), which is was now convinced that her sister had been again a probable indicator of neuro-organic J Neurol Neurosurg Psychiatry: first published as 10.1136/jnnp.58.4.499 on 1 April 1995. Downloaded from replaced by a different, identical looking per- dysfunction. The age graded subtest scores son and that this must have happened in were as follows: information 13, compre- 1942, during the German occupation, when hension 12, arithmetic 9, similarities 10, digit the Germans put other people in the place of span 11, vocabulary 14, digit symbols 7, her relatives. The daughter agreed. The picture completion 3, block design 7, picture mother also started expressing doubts about arrangement 5, object assembly 4. The the identity of her son. She said that "this patient had a particularly low score in the boy" has been behaving irresponsibly by stay- arithmetic subtest of the verbal scale which ing out late at night (contrary to her real son's tests immediate recall, concentration, atten- behaviour). She examined old photographs of tion, and conceptional manipulation. All her son, discovering differences and together, scores in the performance scale were low, mother and daughter, decided that the substi- particularly the picture completion subtest, tution of her son by his double must have which is a test of visual recognition. The sub- happened in 1983, when he first started "mis- scale distribution showed deterioration of the behaving". intellectual abilities of the patient, which They gradually discovered that the double could not be attributed to functional distur- was not just one person. Almost every day, a bance, as the subscales that are sensitive to different person appeared claiming to be the functional disturbance (comprehension, pic- son. They all had similarities but some facial ture arrangement) were within the normal characteristics were different. Mother and range. The Rorschach test did not show dis- daughter eventually started worrying about turbance in reality testing. A drug induced the fate of the real son. sleep EEG and an EEG after sleep depriva- At Christmas 1991 they had an open dis- tion showed abundant paroxysmal bursts of cussion with the double and asked him to slow waves, within the theta and delta range, leave the house. They also reported to the as well as spike like formations, with definite police the disappearance of the son, incrimi- left preponderance more pronounced in the nating his double. frontal-temporal area. Brain CT was normal. The patients were eventually admitted to The patients were on neuroleptic treatment hospital under a compulsory admission sec- when the psychological tests and EEGs were tion after an application by 25 neighbours carried out, but the abnormalities detected and an arson attempt on the neighbouring were qualitatively and quantitatively different apartment. from those that might be attributed to the On admission the mother expressed her influence of neuroleptics. Both patients conviction that she and her daughter had were treated with neuroleptics and carba- been admitted to hospital to be executed. She mazepine. To secure their cooperation they refused to be placed in a different ward to were originally admitted to hospital in the that of her daughter and warned the staff that same ward but after three months the daugh- she would not cooperate if her request was ter was transferred to the day hospital. not satisfied. Originally the patients refused to see any of Physical examination and routine labora- their relatives except the mother's sister, iden- tory tests were normal. Benton's visual reten- tified as a "friend", and their attitude towards http://jnnp.bmj.com/ tion test and Rey's copy of a complex figure the son was reserved and at times hostile, but test showed evidence of disturbance of visual two months after onset of treatment they retention and visual-spatial ability suggestive became more tolerant of him and agreed that of organic cerebral dysfunction. Wechsler's the mother's sister might indeed be more adult intelligence test (WAIS) showed a ver- than a mere "friend". bal IQ of 86, a performance IQ of 79, and a Shortly after separation from her mother, mean IQ of 82. An EEG after sleep depriva- the daughter's indifference gave way to her ex- on October 2, 2021 by guest. Protected copyright. tion was normal, with the exception of rare pressed wish to resume her law studies. Both theta and delta waves, more pronounced on patients agreed to see the son but they showed the left. Brain CT was normal. no positive feelings when he visited them. The daughter was anxious on admission Six months after admission, both patients and kept close to her mother. She expressed agreed to have the son live with them. When ideas of persecution and delusions of doubles, asked who he was, the mother expressed identical in content to those of her mother.