A large number of case studies on Cotard's syndrome have reported that this syndrome develops after repeated episodes of depression in the presenile stage of life. Therefore, it has been defined as a severe type of affective spectrum disorder. This report describes three patients who exhibited symptoms characteristic of Cotard's syndrome, such as negative thoughts and delusions of immortality, in the presenile and senile stages of their lives. They also had a history of long-term treatment for schizophrenia based on a diagnosis in early adulthood. Our review of reports on Cotard's syndrome revealed that the syndrome is more prevalent among presenile and senile female patients, who initially visit psychiatrists in their involutional and presenile stages of life with symptoms of an affective spectrum disorder, and later exhibit the symptoms of Cotard's syndrome. The results of the three case studies suggest that biological factors related to aging and sex differences may be associated with the development of Cotard's syndrome, regardless of the primary disorder. The pathology of "involutional and senile-onset endogenous psychosis," including Cotard's syndrome, is also discussed.
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