Syndrome of subjective doubles

Overview
The syndrome of subjective doubles is a rare delusional misidentification syndrome in which a person suffers from the delusion that he or she has a double or doppelgänger with the same appearance, but usually with different character traits and leading a life of its own. Sometimes the patient has the idea that there is more than one double. The syndrome is usually the result of a neurological disorder, mental disorder or some form of brain damage, particularly to the right cerebral hemisphere.

Sometimes the delusion takes the form of a conviction that whole or part of the patient's personality has been transferred into another person. In this case depersonalization may be a symptom. One example from medical literature is of a man who became depersonalized after an operation and was convinced his brain had been placed into someone else's head. He later claimed he recognized this person.

The syndrome is sometimes comorbid with Capgras delusion, leading to it to be named "subjective Capgras syndrome" in some instances.