Dissociative Ientity Disorder, as defined by the American Psychiatric Association's Diagnostic and Statistical Manual of Mental Disorders (DSM), is a psychiatric diagnosis that describes a condition in which a single person displays multiple distinct identities or personalities, each with its own pattern of perceiving and interacting with the environment. The diagnosis requires that at least two personalities routinely take control of the individual's behavior with an associated memory loss that goes beyond normal forgetfulness; in addition, symptoms cannot be due to substance abuse or medical condition. Earlier versions of the DSM named the condition multiple personality disorder (MPD) and the term is still used by the ICD-10. There is controversy around the existence, possible causes, appearance across cultures, and epidemiology of the condition.