SIR: Capgras syndrome has been defined as the delusional belief in the existence of "doubles" of significant people in a patient's life.⁺¹ We report the case of a socially isolated woman who felt her canary was replaced by a duplicate.

Mrs. G., a 67-year-old woman, was admitted for the first time to a psychiatric hospital for late paraphrenia. On admission she reported delusions of impoverishment and the feeling of being sexually harassed by various men in public. She had been a widow for 11 years, had no children, and lived on her own with very few social contacts. Furthermore, she suffered from concerns that her canary was alone at home. She was delighted with the suggestion that the bird be transferred to the ward. However, during the first two days she repeatedly asserted that the canary in the cage was not her canary and reported that the bird looked exactly like her canary, but was in fact a duplicate. There were otherwise no misidentifications of persons or objects. The paranoid symptoms were rapidly controlled by 3 mg po haloperidol. A CT scan of the brain and an EEG revealed no abnormalities.

Delusions of substitutions of people and objects are well recognized in psychiatric illnesses.⁺² Capgras syndrome, first described by Capgras and Reboul-Lacheaux,⁺³ is known to appear mainly in paranoid psychosis, as in the original description, or in organic brain syndromes including Alzheimer's disease and traumatic brain injury. There are, however, very few cases of Capgras syndrome involving animals.⁺⁴ In Capgras syndrome, a key figure in the patient's life is believed to be replaced by a "double" or imposter. Usually the misidentification involves a person with whom the patient has an "intense affective sentiment."⁺¹ Our patient had no close person in her own environment who fulfilled this role. Instead, her canary had become her closest living companion. Social isolation and loneliness in old age has long been regarded as a factor in the etiology of late paraphrenia.⁺⁵ In the case of Mrs. G., the lack of personal contact in her social environment may have identified her pet canary as the focus for her delusion.