Childhood trauma, such as physical, sexual or emotional abuse, is believed to be the chief trigger of dissociative identity disorder (DID). Other stressors that can trigger the condition include combat, natural disasters, kidnapping, torture and invasive medical procedures. In addition, genetic components may be a factor. Studies have shown that DID is more common in people who have a first-degree relative with the disorder.

Children who experience extreme stress, such as those who have been abused, may develop DID as a means of coping with the trauma. Children also have a greater ability than adults to step outside themselves and observe trauma in a third-person fashion. Children who dissociate in this way as a means of coping may continue to use the practice as adults whenever they are confronted with stress or anxiety-producing situations.