The story of Dr. Jekyll and Mr. Hyde has been the part of many English syllabuses and in most probability was the first introduction of the concept of split personality disorder to young minds. Split personality disorder is a life altering condition, which although not directly life threatening, can have somewhat equal repercussions.

Split personality disorder is also known as dissociative identity disorder or multiple personality disorder. The causes of split personality disorder are mainly psychological factors, like child abuse, traumatic childhood experiences like loss of a near one, intensive humiliation; neglected childhood and difficulty adapting to change. Apart from psychological factors, tangible factors include iatrogenesis that is the adverse effect of medical treatment, that could be medicines or psychological treatment. The causes differ from person to person and it is not necessary that split personality disorder develops its roots only in childhood. In some cases, an adult may suffer from chronic stress, inability to cope with pressures or adapt to change, and as a way out of his depressing situation, develops a split personality which takes control of his original self. Sometimes, people are so greatly affected or influenced by some incident or person, that the feelings resurface as another personality and the person lives a different life, the kind he wished for but could not given his real situation.
Since split personality disorder is a psychological condition, its causes and symptoms vary with every person. The most common symptoms include opinions or behavior which is incongruent. For example: a person may give an impression of being quiet and introverted but in another situation he may behave surprisingly out going. Panic attacks, a general sense of paranoia with no explained reason, recurring nightmares of previous incidents, staying away from family or friends, acute depression, unreasonable phobias or mood swings, are some of the symptoms which are generally seen. In some cases, the person is so deep into his condition that both the personalities exist finely tuned and symptoms may be invisible to the ordinary eye. As such, the symptoms of split personality disorder are such that they can be misunderstood as general human behavior but repeated cases of inexplicable behavior should be taken seriously as there can be a deep psychological reason behind it.
The diagnosis of split personality disorder is mainly done by understanding the psychiatric history of the person by various interview sessions. The different kinds of interview schedules are Dissociative Experiences Scale, Dissociative Disorders Interview Schedule and Structured Clinical Interview.
Treatment for psychological disorders has as much impact for the patient as for his family. During treatment, a person may suffer from extreme mood swings and confusion. The treatment involves psychotherapy where the objective is to reconcile the multiple personalities into one which the person naturally was. Method of doing this could involve being non responsive to the other personalities or ask them to listen to the natural self. Treatment for this condition requires sensitivity and proper understanding and should be performed only an experienced professional. Family members need to be supportive even if their support is met with resentment.
Jekyll and Hyde might have been a fun story to read but person suffering from split personality disorder has a tough time and he requires support from all factions to enjoy life normally.