The document discusses dissociative identity disorder (DID), previously known as multiple personality disorder (MPD). It notes that there remains debate about the exact nature and causes of DID within the research and clinical communities. While some experts believe it may be an "offshoot" of other disorders like schizophrenia, brain imaging studies have found neurological differences in DID patients. The document also explains that the disorder involves a lack of a singular, cohesive identity rather than having multiple distinct personalities. It concludes that more research is still needed to determine if MPD exists as its own diagnosis or is properly classified as DID.