Dissociative Identity Disorder (DID) is a mental health condition characterized by the presence of two or more distinct identities or personality states that continually have power over an individuals behavior. These identities, also known as "alters," have their own personal history, traits, likes, and dislikes. DID can lead to gaps in memory, hallucinations, and other problems. The disorder is often the result of severe trauma, such as sexual or physical abuse during childhood, and is thought to be a coping mechanism to distance or detach from the trauma. Symptoms of DID often show up in childhood, between the ages of 5 and 10, but the disorder is usually not diagnosed until adulthood. Treatment typically involves psychotherapy, with the goal of helping individuals gain control over the dissociative process and integrate the different elements of their identity.

DID is a rare psychiatric disorder diagnosed in about 1.5% of the global population, and it is often misdiagnosed, requiring multiple assessments for an accurate diagnosis. Patients with DID often present with self-injurious behavior and suicide attempts. The disorder has been observed and described in several countries and has been associated with terms such as "outer world possession" and "possession by demons." However, trauma and its association came with DID much later. The theory behind DID describes predisposing factors for dissociation, which include an ability to dissociate, overwhelming traumatic experiences that distort reality, creation of alters with specific names and identities, and lack of external stability, which leads to the childs self-soothing to tolerate these stressors. These factors must be present for DID to develop.

It is important to note that people with DID can and do recover with effective treatment from mental health providers who are trained in trauma and dissociation. They can live full and productive lives, and their symptoms and behaviors reflect their fear of dangerous situations due to their histories of childhood trauma. DID is not a rare condition, and it develops in individuals who have experienced severe trauma. Health care providers do not convince patients of past trauma that isnt true, as several studies confirm that DID develops in individuals who have experienced severe trauma. DID is also repeatedly found in people who are unaware of the disorder and in cultures where the condition is unknown.