"Dissociative identity disorder (DID) is a rare mental health condition. It was once known as multiple personality disorder. People who have it have two or more separate personalities. But they often don't know that the other personalities exist. And they can't remember things that happen when the other personalities are active.DID may be a response to childhood trauma. People with DID may form separate personalities to deal with physical and emotional pain.Having separate personalities can change behavior and cause memory loss. And it can affect how a person thinks, feels, and acts. People with DID may feel anxious and stressed about the effects that separate personalities have on their life. mental health professional usually diagnoses DID while treating the person for other conditions like anxiety, depression, or trauma-related disorders.Counseling is usually the main treatment for DID. The goal is to slowly merge the different personality traits together. This is called integration."