The condition you are referring to is known as "dissociative identity disorder" (DID), formerly called multiple personality disorder. It is a mental health condition characterized by the presence of two or more distinct personality states, also known as alters, each with its own unique way of perceiving and interacting with the world.
People with dissociative identity disorder experience gaps in memory and identity, and they may feel as if they are observing themselves from outside their bodies. This phenomenon is often referred to as "dissociation," where there is a disruption in the usual integration of thoughts, feelings, and consciousness.
It is essential to note that DID is a complex and rare disorder, and individuals experiencing it require professional evaluation, diagnosis, and appropriate treatment from mental health experts, typically psychotherapy or counseling. The causes of DID are not entirely understood, but it is believed to result from severe trauma or abuse experienced during childhood.
If you or someone you know is struggling with mental health issues, it's crucial to seek help from qualified healthcare professionals who can provide proper assessment and support.