It is common for a child to adopt a different persona. Role-playing can be a crucial part of a child’s development as he “tries out” different characters. Researchers have speculated that pretending to be an astronaut or a fireman, for example, can allow a youngster to practice making “predictions about others’ actions and thoughts.”
While they are playing, children often believe that they are the astronaut or the fireman. For most youngsters, their game will last only an hour or two, though some can become elaborate and last a long time.
However, when adults believe that they are someone else, it may be a sign of dissociative identity disorder (once known as “multiple personality disorder”).
It is thought that this may result from regularly repeated trauma, such as domestic violence or sexual abuse. The brain tries to protect itself by inventing another personality to gain distance from the previous painful experiences and the knowledge that they may happen again.
Studies have shown that as many as 99 percent of patients with dissociative identity disorder have experienced a pattern of recurring, overwhelming, and life-threatening events.