Dissociative Identity Disorder: Overview and Current Research

Introduction to Dissociative Identity Disorder (DID)

Dissociative Identity Disorder (DID) is a fascinating disorder that is probably the least extensively studied and most debated psychiatric disorder in the history of diagnostic classification. There is also notable lack of a consensus among mental health professionals regarding views on diagnosis and treatment. In one study involving 425 doctoral-level clinicians, nearly one-third believed that a diagnosis of Borderline Personality Disorder was more appropriate than DID. While most psychologists demonstrated belief that DID is a valid diagnosis, 38% believed that DID either likely or definitely could be created through the therapist’s influence, and 15% indicated that DID could likely or definitely develop as a result of exposure to various forms of media (Cormier & Thelen, 1998).

Description of DID

Diagnosis
According to the diagnostic criteria outlined in the current edition of the DSM, diagnosis of DID requires the presence of at least two personalities, with a personality being identified as a entity having a unique pattern of perception, thought, and relational style involving the both the self and the environment. These personalities must also display a pattern of exerting control on the individual’s behavior. Extensive and unusual loss of memory pertaining to personal information another feature of DID. Differential diagnosis generally involves ruling out the effects of chemical substances and medical (as opposed to psychological) conditions. When evaluating children, it is also important to ensure that symptoms are distinguishable from imaginary play (American Psychiatric Association, 2000).

Prevalence & Comorbidity
In clinical populations, the estimated prevalence of DID ranges from 0.5 to 1.0% (Maldonado, Butler, & Spiegel, 2002). In the general population, estimates of prevalence are somewhat higher, ranging from 1-5% (Rubin & Zorumski, 2005). Females are more likely to receive a diagnosis of DID, at a ratio of 9:1 (Lewis-Hall, 2002). This author also contends that the disproportionately high number of females diagnosed with DID dispels the notion that incestual abuse is largely responsible for the development of DID.

High percentages of individuals with DID have comorbid diagnoses of Post-Traumatic Stress Disorder or Borderline Personality Disorder (Gleaves, May, & Cardeña, 2001). In addition, individuals diagnosed with DID commonly have a previous diagnosis of Schizophrenia. However, this most likely represents a misdiagnosis rather than comorbidity, due to the fact that both disorders involve experiencing Schneiderian symptoms (ibid.). Other possible comorbid disorders involve substance abuse, eating disorders, somatoform disorders, problems of anxiety and mood, personality disorders, psychotic disorders, and organic mental disorders (ISSD, 2005), OCD, or some combination of conversion and somatoform disorder (Kaplan & Sadock, 2008). While the symptoms of DID are complex in themselves, the presence of multiple additional symptoms further complicates diagnosis and treatment.

Client characteristics, course, & prognosis
The course and prognosis of untreated DID is uncertain, and for individuals with comorbid disorders, prognosis is less favorable. Other factors influencing a poor prognosis include remaining in abusive situations, involvement with criminal activity, substance abuse, eating disorders, or antisocial personality features. Although DID occurs more frequently in the late adolescence or early adult age groups, the average age of diagnosis is thirty, with most diagnoses occurring 5-10 years after the onset of symptoms. A risk factor involves having first-degree relatives who have received diagnoses of DID (Kaplan & Sadock, 2008).

Risk factors
One study found that the risk of developing a dissociative disorder (DD) increased seven times with a child’s exposure to trauma. A later diagnosis of DD was twice as likely when the child’s mother had experienced trauma within two years of the child’s birth (Pasquini, Liotti, Mazzotti, Fassone, & Picardi et al. 2002). Dissociative Identity Disorder is linked to childhood abuse in 95-98% of the cases (Korol, 2008). However, other factors in addition to a history of abuse, such as disorganized or disoriented attachment style and a lack of social or familial support best predict that an individual will develop DID (ibid).

Studies on genetic factors contributing to DID present mixed findings. However, one study involving dyzogotic and monozygotic twins found that considerable variance in experiences of pathological dissociation could be attributed to both shared and non-shared environmental experiences, but heritability appeared to have no effect (Waller & Ross, 1997). Another study utilizing objective ratings of dissociative behavior found that shared environmental factors had little effect in both adopted siblings and twin pairs (Becker-Blease, et al, 2004). However, dissociative behavioral correlations of r = 0.21 for fraternal twins and r = 0.60 for identical twins suggests the presence of a genetic effect. As this study did not specifically investigate pathological dissociation, more research is needed to determine if the genetic tendency to experience dissociation varies according to type of dissociation (pathological or non-pathological), and whether trauma influences the pathological development of a pre-existing tendency to dissociate.

Multicultural considerations
Samples of participants from the United States, Canada, the Netherlands, Norway, and Turkey found a similar prevalence estimates (Kluft & Foot, 1999). However, prevalence in India, Germany, and Japan is much lower (Fujii, Suzuki, Sato, Muraka, & Takahashi, 1998). A study conducted with inpatient, outpatient, and the general population in China found prevalence rates of 0.5, 0.3, and 0.0%, respectively (Xiao, et al., 2006). Factors related to individualistic and collectivistic cultures may contribute to the prevalence and etiology of DID. According to Fujii et al., not only are reports of DID in Japan are far more scarce than in North America, but other differences also exist. While most North Americans participants with DID were physically or sexually abused in childhood, Japanese participants diagnosed with DID were far less likely to have experienced physical or sexual abuse. The North American participants in this study also had nearly three times as many alter personalities as Japanese participants.

Treatment of Dissociative Identity Disorder

Psychotherapy
Although the ultimate goal of treatment is integrated functioning of the alter personalities (ISSD, 2005), the presence of multiple comorbid disorders, experiences of trauma, and safety concerns make a comprehensive treatment plan necessary. The International Society for the Study of Dissociation (ISSD) published some basic guidelines to aid clinicians in treating DID. Treatment most commonly follows a framework of “1) safety, stabilization and symptom reduction, 2) working directly and in depth with traumatic memories, and 3) identity integration and rehabilitation” (p. 89).

A study involving 280 outpatient participants (98% DID diagnosis) from five different races (Caucasian, African American, Hispanic, Asian, and Other) demonstrated the effectiveness of a similar five-phase model in reducing symptoms of dissociation. As might be expected from successful treatment, clients in later phases of treatment reported less self-harming behavior, symptom reduction, and more positive behavior than clients in stage 1, as indicated by scores on the Dissociative Experiences Scale II, the Posttraumatic Stress Checklist-Civilian, and the Symptom Checklist-90-Revised (Brand, et al., 2009).Continued on Next Page »