Essay from the year 2022 in the subject English Language and Literature Studies - Literature, grade: 85, language: English, abstract: This work is about dualism in the novel "The Strange Case of Dr. Jekyll and Mr. Hyde" by Robert Stevenson. This research aims to analyze the multiple personality disorder that can be found in the novel entitled "The Strange Case of Dr Jekyll and Mr Hyde" by Robert Stevenson. There are three aims of this study. First, how multiple personality disorders are caused in the main character. Second, understand how the main character dealt with multiple personality disorders? The third one is, to figure out the effects of the disorder in the character's life? The data were described and analyzed through the use of Freud's psychoanalytic theory, where the research aims to discover the two different personalities that the protagonist suffers from. The protagonist can be Dr. Jekyll, the friendly and intelligent person, or Mr. Hyde, the evil and criminal. Multiple personality disorder has bad effects on the main character. The idea of dual human nature does not stand alone between the men, even if they do not accept it. The relationship between Dr. Jekyll and Mr. Hyde is now dismissed by Dr. Jekyll because it does not match what the intelligent scientist believes. The immoral acts are all from Mr. Hyde, while Dr. Jekyll doesn't know what Mr. Hyde is doing because when this character appears, he becomes unconscious. In the end, the multiple personality disorder brought him to death. As stated in the novel, he commits suicide to end his suffering and stops Mr. Hyde. Effects confirm that multiple personality disorders caused a messy life psychologically and physically.