Identifying Dissociative Identity Disorder

Dissociative disorders are often misunderstood and can manifest in various ways, significantly affecting individuals' perception of self and reality. Among these disorders, dissociative identity disorder (DID) is one of the most complex. Recent research suggests that the development of DID may be influenced by significant psychological trauma during formative years. As a clinical psychologist assessing a patient with suspected dissociative identity disorder, which of the following symptoms is most definitive in distinguishing DID from other dissociative disorders, such as dissociative amnesia or depersonalization/derealization disorder?