Split personality crime: who is guilty?
http://www.newscientist.com/article/mg2 ... uilty.html?
05 July 2012 by Jessica Hamzelou
Magazine issue 2872.
For similar stories, visit the Crime and Forensics , Mental Health and The Human Brain Topic Guides
JOHN WOODS was a smart college student in a loving relationship. That was until he saw an unfamiliar footprint on his girlfriend's carpet. The couple argued, and Woods suffocated her. He also stabbed her roommate to death when she tried to intervene.
But Woods escaped the death penalty. The court took into account a psychiatric assessment performed after the crime, which concluded that Woods had multiple personality disorder - formally known as dissociative identity disorder (DID). The crime was not the work of John, but of his insane "alter", Ron.
Bill Greene was also diagnosed with DID following his arrest for kidnapping - but the information was considered inadmissible in court.
Two cases involving DID, two different outcomes. The reason for the contrast is simple: the scientific community has long struggled to establish whether DID is a real condition or simply the work of an overactive imagination. "Washington state [where Greene was tried] said DID wasn't scientifically accepted enough to be considered," says Elyn Saks, who specialises in law and mental health at the University of Southern California, Los Angeles.
A new study could be an important step towards demonstrating that the disorder is real. As such, it might persuade more judges to allow a DID diagnosis to be given as evidence.
People diagnosed with DID have two or more personalities that reveal themselves at separate times. The personalities may not even be aware of each other's existence. "One body holds different identity states that have their own way of thinking about themselves and the environment," says Simone Reinders at Kings College London. The personalities - which can access different sets of memories, and be different ages and genders - are thought to arise as a result of trauma experienced at a young age.
"All of the DID patients I have met report abuse before the age of 4 - the age at which most children develop a distinction between the self and others," says John Morton, who studies memory in DID at University College London. "Normally the abuser is a family member or caregiver, so the children develop two interpretations of the same person - one as a caregiver and one as an abuser. These two have to be kept separate." Young children are thought to cope by developing different personalities - one to deal with the trauma and one that either doesn't remember the abuse or understands it as happening to someone else.
So the theory goes anyway. One of the main arguments made by DID sceptics is that people who show these symptoms are simply prone to fantasising, and have become enamoured with the idea of the disorder through characters such as Sméagol and Gollum in The Lord of the Rings. "Sceptics say people who display multiple personalities are just role playing," says Reinders.
To investigate whether this might be the case, Reinders and her colleagues at the University of Groningen, the Netherlands, studied the brain activity of people who had previously been diagnosed with DID, and compared it with the brain activity of people who do not fall under that diagnosis but are known to fantasise. They also assessed people who are much less prone to fantasising.
The participants with DID were asked to give an example of a traumatic experience that one of their identities was aware of and one was not. Reinders's team then used PET scans to look at the brain activity of these participants as they were reminded of the trauma while in the identity state that was aware of the experience. The researchers repeated the exercise when the participants were in an identity state unaware of the trauma.
Those who had not been diagnosed with DID were asked to imagine they had distinct personalities - only one of whom was aware of a trauma that they had experienced. They, too, were PET scanned while reminded of the trauma twice: once in the personality aware of the experience and once in the personality unaware of the event.
None of the people who were not diagnosed with DID were able to mimic the brain activation patterns seen in the individuals who were, says Reinders (PLoS One, DOI: 10.1371/journal.pone.0039279). "The responses we find in DID patients are not due to fantasy proneness."
"It's a fine paper," says Harald Merckelbach, a DID-sceptic at Maastricht University in the Netherlands. "It shows that people with DID really do have a disorder. I think non-believers would be convinced."
But Stephen Morse, who specialises in criminal and mental health law at the University of Pennsylvania in Philadelphia, thinks that those non-believers might need more evidence. "It would be helpful if these findings were replicated in another laboratory," he says.
"The critical question is: if DID is a genuine disorder, what follows legally?" Morse adds. If a defendant has DID, and the alter personalities are not aware of all the others, there are those who argue that it's not fair to punish all of them, he says.
"I can see a judge concluding that the evidence for DID is not strong enough to admit it into evidence, but the current study might alter that opinion."
Saks agrees. "I think it would help jurors understand that DID is not exclusively something feigned but can be a real disorder," she says. "It would be pretty persuasive."