Research on Dissociative Identity Disorder


Slogar, S. (2011). “Dissociative Identity Disorder: Overview and Current Research.” Inquiries Journal/Student Pulse, 3(05). Retrieved from

Dissociative Identity Disorder: Overview and Current Research

By Sue-Mei Slogar
2011, VOL. 3 NO. 05


This paper entails a description of factors related to diagnosis and treatment of Dissociative Identity Disorder. Epidemiology, including risk factors and sociocultural aspects of the disorder are presented, along with recommendations for treatment. Highlights of current research focusing on neurobiological and psychobiological aspects of DID provide additional insight into providing accurate diagnosis and appropriate treatment. Recommendations for future research involve studies that will elaborate on research already completed, and provide a more detailed analysis of the characteristics of this unique and complex disorder.

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


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


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).

While elements of each phase occur throughout treatment, these phases describe the dominant concerns of therapy during the stages of treatment. Because of the intense feelings experienced as a result of trauma, individuals with DID may behave in ways that facilitate exploitation or are dangerous to themselves or others. Thus, a primary goal for treatment is to manage these behaviors and teach impulse control with some form of cognitive or behavioral therapy. Even when amnesia exists between alters, therapists should hold the client responsible for behaviors of all alters. Therapists should also realize that some clients do not desire fusion or integration of their personalities. In this case, the goal of treatment would involve working towards cooperative functioning of alters. In working with alters, therapists should view alters not as problems to be removed, but as the client’s creative response to trauma. Identifying relationships between alters and communicating with alters directly are strategies useful in treating DID. Requesting that the client listen inwardly to alters may facilitate necessary discussion among alters and between the therapist and client (ISSD, 2005).


No randomized trials have been conducted to compare the effectiveness of various theoretical orientations or medications in treating DID. However, a survey of psychiatrists treating DID found that the most favored treatment methods involved individual therapy, anxiolytics, and antidepressants (Sno & Schalken, 1999). In addition to these drugs, carbamazapine for use electroencephalograph abnormalities, prazosin for nightmares, and naltrexone for self-injurious behavior might be helpful (Kaplan & Sadock, 2008). Although research involving pharmacotherapy for DID is scarce, two studies involving diazepam and perospirone seem promising.

Following unsuccessful treatment with antidepressants and tranquilizers, Okugawa, Nobuhara, Kitashiro, and Kinoshita (2005) examined the effects of treating DID with perospirone, a medication originally intended for the treatment of schizophrenia. The clinical features of this case involve two alternate personalities, who presented as a male (23 years) and a female (17 years). The client (host) was female and 30 years old, and had been diagnosed with DID for 13 years. During presentation of the young female personality, the client reported hearing the male alter, which was her primary symptom, along with anxiety and identity dissociation. The client experienced remission of anxiety and hallucinatory symptoms after a month of treatment with perospirone. Treatment was continued for 5 months, and medication was gradually reduced over a period of 9 months. At the time of writing, the client had experienced remission of dissociative symptoms for 1 year. The results of this case study seem remarkable, especially because use of medication alone was responsible for drastic and sustained improvement in functioning, and continued use of medication was not required to maintain remission of symptoms.

Another case study conducted by Ballew, Morgan, and Lippmann (2003) suggests that diazepam’s anxiety-reducing properties may prove especially useful for assisting in memory retrieval in cases of DID where memories contain traumatic materials. In this study, diazepam was used to successfully facilitate memory retrieval in an amnestic client who was unable to recall his location or identity. The authors of this study concluded that “Intravenous diazepam is aneffective, safe intervention to consider for facilitation ofmemory retrieval in amnestic patients,” and DID can involve some degree of amnesia (p. 347). However, because the efficacy and safety of diazepam has not been demonstrated in the treatment of an adequate number of cases of dissociative disorders, it is difficult to generalize these findings or assess the appropriateness of this treatment. Medication is generally applicable to secondary features and comorbid disorders, and not DID itself.

Integrative treatment plan

Considering the complexity of DID and the lack of conclusive research on treatment methods, the best treatment approach would involve an integrative style. The use of medication for anxiety and trauma-related symptoms and the phase approach allows for immediate treatment of distressing symptoms, flexibility, and a continual evaluation of progress. Depending on which theoretical orientation is more appropriate, various psychotherapeutic modalities can be used to address specific problems as necessary. Inflexibly using one approach may hinder successful treatment, especially because DID often involves comorbid disorders that may need to be considered separately. In addition to integrative individual treatment, Kaplan and Sadock (2008) suggest that familiarity with systems theory and somatoform disorders may be helpful to the therapist in understanding the client’s somatic symptoms and relationships between alters.

Because research supports the importance of social support as a preventative factor, all efforts should be made to discover sources of support for the client once stability is achieved. Group psychotherapy is one way to achieve this goal. Advantages of group therapy include reducing isolation related to a diagnosis of DID, the opportunity to interact with both genders in heterogeneous groups, and an accepting peer group that replaces the secrecy and isolation surrounding childhood abuse. Group therapy provides clients with the opportunity observe others and learn the purpose of alters, and hope for their own recovery as others in the group improve (Buchele, 1993 There are advantages and disadvantages to every treatment method, and it is the responsibility of the therapist to explore feasible options and empower clients in their recovery.

Research and Conclusions

Current research

Research trends currently focus on neurobiological and psychobiological factors unique to this disorder. For example, one study investigated the differences between alters who have access to traumatic memories and alters who suppress such information. The results indicate that different alters demonstrate differences in emotional, sensori-motor, cardiovascular, and regional cerebral blood flow in response to traumatic memories (Reinders, et al., 2006).

Another study sought to apply known findings about related disorders to DID. Because individuals diagnosed with disorders involving an etiology of stress (e.g., Post-Traumatic Sstress Disorder, Borderline Personality Disorder, Major Depressive Disorder with childhood trauma) have demonstrated a reduction in hippocampal volume, the authors of this study used magnetic resonance imaging and volumetric analyses to determine if any relationship also existed between DID and reduced hippocampal volume. Results indicated that the volume of the hippocampus of participants with DID was 19.2% smaller and the amygdala was 31.6% smaller than normal controls (Vermetten, Schmahl, Lindner, Loewenstein, & Bremner, 2006).

Other studies have discovered findings that are relevant to the relationship between trauma and memory in DID. A case study investigating the neural correlates of switching between alters used functional magnetic resonance imaging to study changes in the brain during switching. The results indicated that during switching to the alternate personality, the client’s bilateral hippocampus was inhibited, as well as the right parahippocampal gyrus, right medial temporal lobe, globus pallidus, and substantia nigra. However, during transition to the host personality, the right hippocampus demonstrated evidence of increased activation, with no inhibition in any brain structures (Tsai, Condi, Wu, & Chang, 1999). These findings contribute to an understanding of amnesia between alters, since regions of the brain involved in memory are either inhibited or activated.

Other research supports the idea that alters develop to protect the host from unpleasant thoughts and memories involving trauma and abuse. Autobiographical memories may differ between alter personalities, allowing the host to retain positive memories while alters contain negative traumatic memories (Bryant, 2005). A study investigating directed forgetting found that “dissociative patients showed directed forgetting between states, but not within the same identity state” (p. 241). This study clarifies the mechanism and function of memory in various dissociative states and helps explain why trauma might result in the development of alters. Pushing threatening material out of consciousness can then be facilitated by a switch from one state of consciousness to another (Elzinga, Phaf, Ardon, & van Dyck, 2003).

Future direction

While clinicians now understand more about DID than in the past, additional research is needed to clarify and further investigate the nature of DID. The research that has been completed on this disorder still leaves many questions unanswered. For example, future research should further examine risk factors, and clarify how genetic and environmental factors contribute to this disorder. More studies should determine the nature of the physical and psychological differences evident among alters, how they develop, and their significance. Psychopharmacological studies are needed to determine which medications work best, and why they are effective.

Multicultural research is necessary to determine how sociocultural factors affect the development and clinical presentation of DID. Additional research in this area will not only benefit individuals with DID and their families, but also the research and clinical psychology community as a whole. Gaining an improved understanding of Dissociative Identity Disorder involves more than the categorization of another mental disorder. Increased knowledge in this area also contributes to an improved understanding of the nature of consciousness and the mind-brain relationship, as well.


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