Introduction and objective:
Cotard’s syndrome is one of the less common psychiatric disorders. It is defined as a syndrome characterized by the presence of nihilistic delusions which, depending on the course of the illness, can focus on beliefs about one’s own death, the non-existence of internal organs, or the process of their decomposition. Sometimes, external elements of the world can also become the objects of delusions.

Review methods:
This article was based on a systematic review of original articles describing case studies of various patients suffering from Cotard’s syndrome, as well as reviews focusing on understanding the specific nature of this disorder and its underlying causes.

Brief description of the state of knowledge:
Considering the rarity of Cotard’s syndrome, it has not been included in any list of medical conditions, including the ICD-10, ICD-11, or DSM-V classification. When diagnosing patients suspected of Cotard’s syndrome attention should be paid to increased feelings of anxiety, sometimes accompanied by a sense of guilt that cannot be explained by rational causes. Over time, nihilistic delusions also appear, with the key aspect being the patient’s denial of reality.

Summary:
Cotard’s syndrome may manifest in patients as an independent disorder or coexist with other medical conditions such as schizophrenia, depression, anxiety disorders, Parkinson’s disease, or stroke. Depending on the underlying cause of symptoms, different therapeutic approaches may be necessary. Recognizing the significance of coordinated collaboration among doctors of various specialties is crucial in diagnosing this extremely rare disorder.