What Are the Causes of Split Personalities?

In the 1976 film "Sybil," Sally Field portrayed a woman with at least 12 separate identities, an example of split personality also known as dissociative identity disorder. People with this disorder have usually suffered some kind of trauma that results in a manifestation of various personalities that may not even be aware of each other. Some suspected causes of split personality disorder include physical and sexual abuse, temporal lobe epilepsy and extreme traumatic events.

Physical Abuse

• Some people who have experienced repeated physical abuse during their childhood may develop a split personality as a way to escape the pain and shame of the abuse they suffered. In many of these cases, the person experiencing the physical abuse feels there is no way to prevent the abuse and retreats into her own mind, creating one or more separate personalities distinct from the one suffering the abuse.

Sexual Abuse

• According to the Cleveland Clinic Medical Institutes, childhood trauma associated with sexual abuse can result in split personality disorder. Though it's true that not everyone who suffered from sexual abuse manifests a split personality, the shame and guilt often associated with that crime can instill a sense of helplessness in the sufferer that's only relieved by dissociating from painful thoughts and feelings, and escaping into another personality. Often, the lack of an authority figure to provide support during the time the sexual abuse was occurring can contribute to the formation of a split personality.

Temporal Lobe Epilepsy

• People with temporal lobe epilepsy experience seizures in the temporal lobe, which controls the olfactory process, memory skills and emotion. Temporal lobe seizures have been identified as a possible trigger for split personality disorder. In 2005, two Minnesota researchers performed a case study on an adult patient who experienced frequent temporal lobe seizures and observed significant dissociative symptoms such as changes in facial expression, tone of voice and speech as alternate personalities emerged -- including that of a 4-year-old girl. However, not everyone who suffers from temporal lobe epilepsy develops a split personality.

Extreme Traumatic Events

• Life-changing events such as war, natural disasters, kidnapping and torture are other causes of split personality disorder. Because these are sustained events that don't disappear after a day or two, survivors may mentally escape those situations by creating personalities that are completely dissociated from the pain and horror of what is actually happening, and create worlds and situations that bear no resemblance to reality. According to the Sidran Traumatic Stress Institute, dissociation during traumatic events can help a person cope with something that would otherwise overwhelm them, but a sustained dissociative state makes it difficult for a person to function normally because any stressful situation triggers the occurrence of a split personality.