Syndrome of subjective doubles

Syndrome of subjective doubles is a rare delusional misidentification syndrome in which a person holds the fixed belief that they have a double, a doppelganger who looks the same as they do but usually has different character traits and is living a life of its own. Some patients believe there is more than one double, and the double may be projected onto anyone, from a stranger to a family member. The syndrome is often diagnosed during or after the onset of another mental disorder, such as schizophrenia or other disorders involving psychotic hallucinations. No widely accepted treatment exists, and most patients need individualized therapy. Few cases have been reported since the condition was defined in 1978 by the Greek-American psychiatrist George Nikolaos Christodoulou, and because the literature does not define it clearly it may be under-reported. It is also called the syndrome of doubles of the self or the delusion of subjective doubles.