A new study published Wednesday in the journal Acta Psychiatrica Scandinavica is sure to add more fuel to a debate among mental health professionals that’s been smoldering for decades — one concerning the true origin of multiple personalities.

The European researchers set out to break a stalemate concerning the scientific consensus surrounding dissociative identity disorder (DID), a psychological condition that was first classified as multiple personality disorder in the third edition of the Diagnostic and Statistical Manual of Mental Disorders, the diagnostic bible of the mental health field, in 1980. People who are diagnosed with DID are considered to have two or more distinctive personality states, or identities. Someone with the condition also has a particular form of memory impairment, such that their main identity often can’t remember the experiences of the alter egos, and a consistent sense of feeling disconnected from reality. But the reason why a person’s very self might split apart has been hotly contested, with some pointing to trauma, while others place the blame on the environment and even manipulative therapists — the current study offers some tantalizing hints of an answer and is likely to stoke further argument.

A Tale Of Two Theories

When the condition first received widespread attention, mental health clinicians universally attributed its cause to horrific trauma experienced by the patient, oftentimes repeatedly, during their childhood. The trauma seemingly triggered a biological defense mechanism in the patient, causing their minds to repress their memories deep into their subconscious, only for them to later emerge in new identities, or alters, walled off from the original self. During the course of treatment, therapists would often discover hidden identities, coaxing them outward through hypnosis and other techniques meant to unlock their repressed memories.

But in the late 80s and 90s, research psychologists and others began to attack this theory of DID’s cause. Rather than being set off by repressed trauma, they argued, the patient’s mind fractured in response to their surroundings, namely their own therapists. In other words, therapists who already believed in the existence of DID could influence particularly susceptible patients to believe they themselves had repressed memories of their trauma as well as multiple personalities. These patients, it was thought, might be susceptible because they had overactive, fantasy-prone imaginations, were more suggestible, or were more likely to create false memories.

In this latest, small study of female DID patients, however, the researchers didn’t find evidence of those three traits. Using a variety of psychological tests and questionnaires, they compared 17 DID patients to matching groups of people who either had post-traumatic stress disorder, actors who mimicked DID symptoms, and healthy controls. They even compared DID patients to themselves by having the majority voluntarily switch from their base personality state to one that had strong traumatic memories. “Patients with diagnosed genuine dissociative identity disorder... were not more fantasy-prone or suggestible and did not generate more false memories compared with the other groups,” the authors wrote.

Adding more support to the trauma-based model of the condition, the DID patients consistently reported a greater history of early trauma than the other control groups, and the more severe their trauma was, the worse their DID symptoms generally were.

There was also evidence that the DID patients weren’t faking it. They showed marked personality differences between the different types of identities they exhibited, and to a greater degree than when the actresses pretended to switch their identities. Earlier research by many of the same authors found that differences between identities could be seen in the brain and physiologically as well.

“Our findings correspond with research in other areas of psychology and psychiatry, which increasingly implicate trauma with mental health disorders such as psychosis, depression, and now, dissociative identity disorder,” said senior study author Dr. Simone Reinders, a professor in the Institute of Psychiatry, Psychology, and Neuroscience at King's College London, in a statement.

Unanswered Questions

While this study is certainly valuable, it’s likely not a definitive tiebreaker. In addition to relying on a very small sample size, the findings from this study and the authors’ earlier research don’t actually prove whether DID is caused by trauma or not.

“For me, the basic hypothesis is hugely not correct,” Dr. Rafaele J. C. Huntjens, a professor and experimental psychologist at the University of Groningen in the Netherlands, told Medical Daily. Huntjens has extensively studied how patients with trauma-related disorders, including DID, process memory. “Finding differences between identities will not decide the argument between the two models,” she said.

Few critics of the trauma model, if any, have argued that the experience of having multiple personalities isn’t real, or that people living with DID are largely lying about their trauma or pain. They’ve argued that the condition isn’t caused by a biological response to trauma, and is instead caused by the unique circumstances of a person’s culture, as well as sometimes the careless use of therapeutic techniques known to induce false memories or distort a patient’s sense of reality.

There is some evidence to back this up. Diagnoses of DID skyrocketed in the United States with the release of Flora Schreiber's 1973 Sybil, a scandalous and immensely popular semibiographical novel about a young woman's struggle with and victory over multiple personalities. The symptoms ascribed to Sybil, whose real name was Shirley Mason, quickly became the template for DID, which had been so obscure that there are only 76 documented cases of the disorder before 1944, with no records of it before the 19th century. As the condition became more popularly known, its symptoms morphed dramatically. While Sybil was said to have sixteen personalities, later cases had alters numbering in the hundreds, and some even considered themselves an animal or inanimate object.

Then there was a backlash. Former patients emerged and told horrific stories of coercive methods that made them believe their mental ills were caused by traumatic memory repression and multiple personalities. The number of diagnoses of DID died down, along with the level of scientific interest, though Huntjens said we have no concrete idea of current worldwide rates. In 2011, journalist Debbie Nathan revealed typed letters and diary entries written by Shirley Mason confessing that similar methods were used on her and that she went along with the act to appease Wilbur. Three years later, Dr. Allen Frances, the chair of the DSM's fourth edition task force, expressed his deep regret in allowing the diagnosis to maintain legitimacy in the mental health profession.

“Having seen hundreds of patients who claimed to house multiple personalities, I have concluded that the diagnosis is always (or at least almost always) a fake, even though the patients claiming it are usually (but not always) sincere,” he wrote in a January 2014 article for Psychology Today.

Perhaps as indirect support for Frances’ assertion, the researchers in the current study found that DID patients scored higher on a test for their degree of malingering, otherwise known as a willingness to fake or exaggerate symptoms.

Elsewhere, a wide range of research has shown that it’s remarkably easy to induce false memories of even heinous crimes. So while the DID group wasn’t any more susceptible to the creation of false memories than anyone else, that finding alone can’t tell us whether their past traumas objectively happened. It also can't tell if or how they led to the splitting of personalities. Huntjens notes that people who believe they were abducted by aliens or experienced other supernatural phenomenon feel the same degree of fear and stress when reminded of it as people do when recalling more documented trauma.

“These people also showed abnormalities in brain activity when they listened to their traumatic stories of being abducted, but that doesn’t show that they were really abducted,” Huntjens said. “Which might mean the hypothesis of finding differences between identities isn’t very valid itself.”

Lastly, there are still many gaping holes with the trauma model of DID not addressed by the study. For one, there’s mixed evidence, some produced by Huntjens and her colleagues, surrounding the claim that DID patients don’t access the memories of their other identities. Patients who believe they don’t remember the information memorized by another identity have objectively been shown — in several studies — to actually retain that information. And the majority of evidence indicates that people who go through trauma have an enhanced memory of the event, not one that’s blinkered out of existence entirely.

A Third Path?

In the paper, the authors document that there have been cases of people who developed symptoms of DID because of sociocultural factors, and that these individuals genuinely believed they had multiple personalities at the time. But they also state that these cases don’t disprove the connection between early childhood trauma and DID. Some researchers argue that both theories of DID could be true to an extent.

Patients diagnosed with DID, both in Sybil’s day and now, have often received years of treatment for a variety of mental health problems such as borderline personality disorder, and many of these conditions have been associated with a history of trauma. Some limited research, including this current study, has also shown that DID patients have more sleep problems than others, which in turn may worsen dissociation and increase the chances of becoming fantasy prone.  

In other words, it’s possible that some people with a combination of trauma history, long-lingering mental illness, and chronic sleep problems could be influenced — whether directly or subtly — to express their very real mental distress through the creation of dissociative identities.

“I think that the core of the disorder is that these people have somehow come to believe and understand their behavior in terms of dissociative identities, but I don’t think they’re completely consciously stimulating their disorder,” Huntjens said. “For example, if someone was anorexic, you wouldn’t think that they’re acting.”

She added, however, that it’s “nonsense” to keep searching for a biological mechanism or cause of DID. Rather, clinicians should search for better ways of helping patients, since the condition is notoriously difficult to treat. Her team is currently in the middle of a trial that aims to treat DID patients through schema therapy, an approach often used with borderline personality disorder patients. Rather than trying to reintegrate a patient’s different identities into one complete self, as conventional treatments often do, her team interprets the person’s identities as different emotional states, with the hope that they can help the patient feel securely attached to all their past experiences.

Heartening as it would to be conclude that this current study wraps up the DID saga, it’s likely only the latest chapter.

Source: Vissia E, Giesen M, Chalavi S, et al. Is it Trauma- or Fantasy-based? Comparing Dissociative Identity Disorder, Post-Traumatic Stress Disorder, Simulators, and Controls. Acta Psychiatrica Scandinavica. 2016.