You may remember the story of Sybil (a pseudonym for Shirley Ardell Mason, who was born in 1923), a person who, over a period of 40 years, claimed to possess 16 distinct personalities. Mason was in therapy for many years trying to integrate these personalities into one complete self. A TV movie about Mason’s life, starring Sally Field as Sybil, appeared in 1976.
Sybil suffered from the most severe of the dissociative disorders, dissociativeidentitydisorder. Dissociative identity disorder is a psychological disorder in which two or moredistinct and individual personalities exist in thesameperson, and thereis an extremememorydisruption regarding personal information about theother personalities (van der Hart & Nijenhuis, 2009). 1 Dissociative identity disorder was once known as “multiple personality disorder,” and this label is still sometimes used. This disorder is sometimes mistakenly referred to as schizophrenia.
In some cases of dissociative identity disorder, there ca n be more than 10 different personalities in one individual. Switches from one personality to another tend to occur suddenly, often triggered by a stressful situation (Gillig, 2009). 2 The host personality is the personality in control of the body most of the time, and the alter personalities tend to differ fr om each other in terms of age, race, gender, language, manners, and even sexual orientation (Kluft, 1996). 3 A shy, introverted individual may develop a boisterous, extroverted alter personality. Each personality has unique memories and social relationships (Dawson, 1990). 4 Women are more frequently diagnosed with dissociative identity disorder than are men, and when they are diagnosed also tend to have more “personalities” (American Psychiatric Association, 2000). 5
The dissociative disorders are relatively rare conditions and are most frequently observed in adolescents and young adults. In part because they are so unusual and difficult to diagnose, clinicians and researchers disagree about the legitimacy of the disorders, and particularly about dissociative identity disorder. Some clinicians argue that the descriptions in the DSMaccurately reflect the symptoms of these patients, whereas others believe that patients are faking, role- playing, or using the disorder as a way to justify behavior (Barry-Walsh, 2005; Kihlstrom, 2004; Lilienfeld & Lynn, 2003; Lipsanen et al., 2004). 6 Even the diagnosis of Shirley Ardell Mason (Sybil) is disputed. Some experts claim that Mason was highly hypnotizable and that her therapist unintentionally “suggested” the existence of her multiple personalities (Miller & Kantrowitz, 1999). 7