Is It Real?

Let’s start with a little history. Multiple personality disorder, or dissociative identity disorder (DID) as it is known now, used to be a mere curiosity. This is a disorder in which people present with more than one personality. For example, at times they might act and identify as an adult while at other times they might identify and behave like a child. dissociative identity disorder (DID) was rarely diagnosed until the 1980s. That is when multiple personality disorder became an official diagnosis in the DSM-3. From then on, the numbers of “multiples” increased rapidly. In the 1990s, there were hundreds of people diagnosed with multiple personality in every major city in the United States (Hacking, 1995). How could this “epidemic” be explained?

One possible explanation might be the media attention that was given to the disorder. It all started with the book The Three Faces of Eve (Thigpen & Cleckley, 1957). This book, and later the movie, was one of the first to speak of multiple personality disorder. However, it wasn’t until years later, when the fictional, as-told-to book of Sybil (Schreiber, 1973) became known worldwide, that the prototype of what it was like to be a “multiple personality” was born. Sybil tells the story of how a clinician—Cornelia Wilbur—unravels the different personalities of her patient Sybil during a long course of treatment (over 2,500 office hours!). Wilbur was one of the first to relate multiple personality to childhood sexual abuse. Probably, this relation between childhood abuse and dissociation has fueled the increase of numbers of multiples from that time on. It motivated therapists to actively seek for clues of childhood abuse in their dissociative patients, well within the mindset of the 1980s, as childhood abuse was a sensitive issue then in psychology as well as in politics (Hacking, 1995).

From then on, many movies and books were made on the subject of multiple personality, and nowadays, we see patients with dissociative identity disorder as guests visiting the Oprah Winfrey show, as if they were our modern-day circus acts.

Despite its controversial nature, dissociative identity disorder (DID) is clearly a legitimate and serious disorder, and although some people may fake symptoms, others suffer their entire lives with it. People with this disorder tend to report a history of childhood trauma, some cases having been corroborated through medical or legal records (Cardeña & Gleaves, 2006). Research by Ross et al. (1990) suggests that in one study about 95% of people with DID were physically and/or sexually abused as children. Of course, not all reports of childhood abuse can be expected to be valid or accurate. However, there is strong evidence that traumatic experiences can cause people to experience states of dissociation, suggesting that dissociative states—including the adoption of multiple personalities—may serve as a psychologically important coping mechanism for threat and danger (Dalenberg et al., 2012).

Sadly, more than 70% of people with DID have attempted suicide, and self-injurious behavior is common among this population. Treatment is crucial to improving quality of life and preventing suicide attempts. Cognitive Behavioral Therapy (CBT) could be used as a mode of treatment for these patients.^[1]

Dissociative Identity Disorder

By far, the most well-known dissociative disorder is dissociative identity disorder. People with dissociative identity disorder exhibit two or more separate personalities or identities, each well-defined and distinct from one another. Those with DID also experience memory gaps for the time during which another identity is in charge (e.g., one might find unfamiliar items in her shopping bags or among her possessions), and in some cases may report hearing voices, such as a child’s voice or the sound of somebody crying (APA, 2013). The study of upstate New York residents mentioned above (Johnson et al., 2006) reported that 1.5% of their sample experienced symptoms consistent with dissociative identity disorder in the previous year. The estimated DID prevalence around the globe is about 5% among the inpatient psychiatric population, 2%-3% among outpatients, and 1% in the general population.^[2]

The DSM-5 gives the following diagnostic criteria for DID:^[3]

Figure 1. A person diagnosed with DID will generally feel a discontinuity in their sense of self and experience changes in identifies—each with their own personalities, names, stories, and mannerisms.

• “Disruption of identity characterized by two or more distinct personality states marked by the discontinuity in the sense of self and agency and accompanied by related alterations in affect, behavior, consciousness, memory, perception, cognition, and/or sensory-motor functioning.
• Recurrent gaps in the recall of everyday events, important personal information, and/or traumatic events that are inconsistent with ordinary forgetting.
• The symptoms cause clinically significant distress or impairment in social, occupational, or other important areas of functioning.
• The disturbance is not a normal part of a broadly accepted cultural or religious practice. Note: In children, the symptoms are not better explained by imaginary playmates or other fantasy play.
• The symptoms are not attributable to the physiological effects of a substance (e.g., blackouts or chaotic behavior during alcohol intoxication) or another medical condition (e.g., complex partial seizures).”

Sense of Self and Agency

The terms sense of self and sense of agency are used in the DSM as it discusses the presence of distinct personality states, better known as alter personalities. Distinct personality states are the discontinuities (switches) between alters, as well as their presence that this criterion describes. A discontinuity in a person’s sense of self can affect any part of someone’s functioning. Attitudes, outlooks, and personal preferences (like preferred foods or clothes) may change suddenly and inexplicably and then change back again. This happens because alter personalities have different attitudes, outlooks, and preferences, so a very sudden change without explanation occurs when an alter has either taken control or is strongly influencing the person. When that alter is no longer active, everything changes back (until the next time the same alter is active). During these shifts, a person may find they have bought clothes they would never choose to wear, or a very outgoing person may suddenly become shy and introverted with no apparent reason.

Discontinuity in a person’s sense of agency means not feeling in control of, or as if you don’t “own” your feelings, thoughts or actions. For example, experiencing thoughts, feelings or actions that seem as if they are “not mine” or “belong to someone else.” This is not the delusional belief that you belong to an outside person; it is the perception that your own speech, thoughts, and/or behavior do not feel like they belong to them and may make no sense to you. Emotions and impulses are often described as puzzling to the person.

In DID some of the thoughts, feelings, or actions of alter personalities intrude into the person’s conscious awareness, even when the person is not aware of having any alter personalities or has amnesia for their actions. This is known as passive influence or partially dissociated intrusions of alter identities into conscious awareness. A person with DID may also experience a fully dissociated intrusion, and may say things like

• “I have no control;, I watch what happens, but can’t stop it.”
• “I find myself coming to in the downtown area where I live, but I won’t remember where I parked the car.”
• “I have found myself crying uncontrollably and sucking my thumb, but I can’t explain why.”
• “Sometimes I’ve had people call me by a name I don’t recognize, and I don’t know who they are.”

Some people describe this combined change of “sense of self” and “sense of agency” as feeling like an experience of possession, in a non-religious sense, or having their body “hijacked.” A person with DID may find that their body feels totally different during this time (e.g., like a small child, the opposite gender, huge and muscular), or may feel as if they are suddenly younger or older.

Causes of DID

Dissociation and Trauma

The most widely held perspective on dissociative symptoms is that they reflect a defensive response to highly aversive events, mostly trauma experiences during the childhood years (Bremner, 2010; Spiegel et al., 2011; Spitzer, Vogel, Barnow, Freyberger, & Grabe, 2007).

As mentioned previously, one prominent interpretation of the origins of dissociative disorders is that they are the direct result of exposure to traumatic experiences, called the post-traumatic model (PTM). According to the PTM, dissociative symptoms can best be understood as mental strategies to cope with or avoid the impact of highly aversive experiences (e.g., Spiegel et al., 2011).

The post-traumatic model casts the clinical observation that dissociative disorders are linked to a trauma history in straightforward, causal terms, that is, one causes the other (Gershuny & Thayer, 1999). For example, Vermetten and colleagues (Vermetten, Schmahl, Lindner, Loewenstein, & Bremner, 2006) found that the DID patients in their study all suffered from PTSD and concluded that DID should be conceptualized as an extreme form of early abuse–related PTSD (Vermetten et al., 2006).

Causality and Evidence

The empirical evidence that trauma leads to dissociative symptoms is the subject of intense debate (Kihlstrom, 2005; Bremner, 2010; Giesbrecht, Lynn, Lilienfeld & Merckelbach, 2010). Three limitations of the PTM will be described below.

First, the majority of studies reporting links between self-reported trauma and dissociation are based on cross-sectional designs. Cross-sectional approaches mean that the data are collected at one point in time. When analyzing this type of data, one can only state whether scoring high on a particular questionnaire (for example, a trauma questionnaire) is indicative of also scoring high on another questionnaire (for example, the DES). This makes it difficult to state if one thing led to another, and therefore if the relation between the two is causal. Thus, the data that these designs yield do not allow for strong causal claims (Merckelbach & Muris, 2002).

Second, whether somebody has experienced trauma is often established using a questionnaire that the person completes himself or herself. This is called a self-report measure. Herein lies the problem. Individuals suffering from dissociative symptoms typically have high fantasy proneness. High fantasy proneness is a character trait to engage in extensive and vivid fantasizing. The tendency to fantasize a lot may increase the risk of exaggerating or understating self-reports of traumatic experiences (Merckelbach et al., 2005; Giesbrecht, Lynn, Lilienfeld, & Merckelbach, 2008).

Third, high dissociative individuals report more cognitive failures than low dissociative individuals. Cognitive failures are everyday slips and lapses, such as failing to notice signposts on the road, forgetting appointments, or bumping into people. This can be seen, in part, in the DSM-5 criteria for DID, in which people may have difficulty recalling everyday events as well as those that are traumatic. People who frequently make such slips and lapses often mistrust their own cognitive capacities. They also tend to overvalue the hints and cues provided by others (Merckelbach, Horselenberg, & Schmidt, 2002; Merckelbach, Muris, Rassin, & Horselenberg, 2000). The overvaluation of hints and clues make them vulnerable to suggestive information, which may distort self-reports, and thus limits conclusions that can be drawn from studies that rely solely on self-reports to investigate the trauma-dissociation link (Merckelbach & Jelicic, 2004).

Most important, however, is that the PTM does not tell us how trauma produces dissociative symptoms. Therefore, workers in the field have searched for other explanations. Clinicians proposed that due to their dreamlike character, dissociative symptoms such as derealization, depersonalization, and absorption are associated with sleep-related experiences. Clinicians further noted that sleep-related experiences can explain the relationship between highly aversive events and dissociative symptoms (Giesbrecht et al., 2008; Watson, 2001).

Controversial Diagnosis

Figure 2. Known as the Hillside Strangler, Kenneth Bianchi faked multiple personality disorder, pleading innocence due to insanity. He was found guilty and sentenced to life in prison.

DID is highly controversial. Some believe that people fake symptoms to avoid the consequences of illegal actions (e.g., “I am not responsible for shoplifting because it was my other personality”). In fact, it has been demonstrated that people are generally skilled at adopting the role of a person with different personalities when they believe it might be advantageous to do so. As an example, Kenneth Bianchi was an infamous serial killer who, along with his cousin, murdered over a dozen females around Los Angeles in the late 1970s. Eventually, he and his cousin were apprehended. At Bianchi’s trial, he pled not guilty by reason of insanity, presenting himself as though he had DID and claiming that a different personality (“Steve Walker”) committed the murders. When these claims were scrutinized, he admitted faking the symptoms and was found guilty (Schwartz, 1981).

A second reason DID is controversial is because rates of the disorder suddenly skyrocketed in the 1980s. More cases of DID were identified during the five years prior to 1986 than in the preceding two centuries (Putnam, Guroff, Silberman, Barban, & Post, 1986). Although this increase may be due to the development of more sophisticated diagnostic techniques, it is also possible that the popularization of DID—helped in part by Sybil, a popular 1970s book (and later film) about a woman with 16 different personalities—may have prompted clinicians to overdiagnose the disorder (Piper & Merskey, 2004). Casting further scrutiny on the existence of multiple personalities or identities is the recent suggestion that the story of Sybil was largely fabricated, and the idea for the book might have been exaggerated (Nathan, 2011).