Capgras delusion is a psychological condition where a person believes that someone close to them, such as a family member or friend, has been replaced by an identical impostor. This delusion can occur in various mental health disorders, including schizophrenia and dementia. The individual may express strong emotions about the perceived impostor, often feeling fear or distrust. The exact cause of Capgras delusion is not fully understood, but it is thought to involve a disconnect between facial recognition and emotional response. This disconnect may lead to the belief that the familiar person is not the same, despite their physical appearance remaining unchanged.