Alternating personalities refers to the phenomenon of a person switching between different identities or personas. This can also be described as multiple personalities, split personality, or dissociative identity disorder. Some other synonyms for alternating personalities include identity switching, personality shifts, the presence of different alters, and multiplicity. These synonyms all describe the same condition where an individual displays different characteristics, moods, and behaviors from one moment to the next. The exact cause of this disorder is not fully understood, but it is often associated with traumatic experiences or abuse during childhood. Treatment typically involves psychotherapy, medication, and support from loved ones.