KNOCK KNOCK tells the story of a man who lives with Dissociative Identity disorder (D.I.D.) - known, until 1994, as Multiple Personality Disorder. It is a rare psychological condition in which two or more distinct identities or personality states, are present in an individual and alternately take control of that individual. The person also experiences extensive memory loss. Usually, the primary identity or ‘host’ carries the individual’s given name and is passive, guilty and or depressed. Each of the identities or ‘alters’ is experienced as though it has a distinct history and self-image with a separate name, reported age, gender and personal history. 

The various identities may or may not like or approve of one another or even know of one another’s existence. D.I.D. is thought to result from severe trauma during childhood. It is a coping mechanism - the person dissociates his / her conscious self from a situation or experience that is too painful to acknowledge.