Category: Integrating

No-one knows why Steven Kazmierczak snapped. When he kicked his way into a packed lecture hall in Northern Illinois University, shooting dead five students and injuring 21 more, those who knew him expressed surprise that he was capable of such brutal violence.

He killed himself at the end of the spree, meaning his motives remain unknown, but the legacy of this tragic event may be more than just the actions of a lone unfathomable killer.

Because when Kazmierczak attacked, a team of psychologists and neuroscientists had already assessed a large group of students who had been recruited as non-affected participants for a study on the effects of victimisation, giving the researchers an unwanted opportunity to better understand how sudden trauma affects the innocent.

Since the 1980s we have recognised a trauma-specific mental disorder. Its name, ‘post-traumatic stress disorder,’ seems to suggest that trauma alone causes the condition but we have known for years that genetics play a large part in determining who does and who doesn’t develop PTSD.

Not everyone who experiences a violent attack, disaster or sexual assault will develop PTSD. In fact, the single most common outcome after tragedy is not mental illness, but recovery. That’s not to say that we wouldn’t feel shaken up or distressed after such events but most people can return to their everyday lives, perhaps changed, but unimpaired.

What we still don’t know is how people who recover are different. Why is it that some individuals develop the disorder following trauma while others appear to be relatively resilient?

We’ve known since studies on Vietnam veterans that genetics accounts for up to 30% of the difference in PTSD symptoms but researchers have been keen to find to specific genes that confer the biggest vulnerability.

Normally these types of studies look at people with and without PTSD and compare the presence of specific genes known to be linked to brain function, to see if they appear more in one group than another. Although helpful, one problem with these sorts of studies is that it is difficult to say whether the genes might directly contribute to the condition or to a general difficulty with mood or behaviour.

In scientific terms, the reason this can be a problem is because people who are already, for example, low in mood or impulsive, are on average more likely to be victimised, attacked or abused. This means it’s difficult to know exactly which genes are most important for explaining the reaction to trauma, rather than the chance of being victimised.

Psychologist Kristina Mercer was leading a study on trauma before the shooting occurred. She had been interviewing female students about their life histories and experience of trauma at Northern Illinois University, originally planning to re-interview the students over time to see which characteristics made them more likely to experience sexual assault.

Clearly motivated to make sure that something more than grief and pain would come from the event, she switched focus to better understand what made some people more likely to develop PTSD after the shooting.

The team re-interviewed the participants in the weeks following the tragedy, assessing their exposure to the violence, any PTSD symptoms present and their level of support from friends and family. A similar interview was conducted 8 to 12 months later and at the end of the study, the researchers took saliva samples to look at the DNA of each participant.

As PTSD is largely a disorder of anxiety accompanied by an intrusive reexperiencing of the event that doesn’t fade with time, the team focused on genes for the serotonin transporter system or SERT.

Serotonin is one of the brain’s neurotransmitters that provide chemical signalling between brain cells. The serotonin transporter system is responsible for removing the used serotonin from the synaptic cleft, the signalling space between the neurons, and putting it back in place, ready to be used again.

This is important because if not removed from the synaptic cleft, the serotonin will keep on signalling. In other words, the efficiency of the serotonin transport system in cleaning-up stray neurotransmitter determines the strength of the signal as much as the original message.

We know that many of the key circuits involved in anxiety are reliant on the serotonin neurotransmitter, so the research team suspected that people with genes differing in how they control transport system could be differently susceptible to anxiety and, perhaps, trauma.

In line with their thinking, the results showed a similar picture. A transport gene called rs25531 was identified as directly linked to the chance of developing PTSD after the shooting. Interestingly, a commonly mentioned serotonin gene, 5-HTTLPR, was only linked to PTSD risk when it was also present with rs25531, suggesting the importance of looking at genetic interactions and not just single genes.

Because of nature of the shootings – a lone gunman who randomly attacked anyone in range – the results are more directly tied to reaction to trauma, rather than a possible vulnerability to being victimised, meaning this is one of the few studies that gives us an unambiguous insight into the post-trauma process.

Now it’s common at this point to say that a discovery of specific genes raising the risk of mental illness should lead to a better treatment for trauma, but this is usually nothing more than a hopeful twist on the scientific details, and this case is no different.

The results suggest no direct treatment and no immediate cure because mind, brain and trauma are too complex for simple solutions.

But the study is no less important. It’s still an essential part of our understanding and provides an essential thread in a tapestry of knowledge.

And fittingly, it shows that even from the shadow of tragedy, light emerges.
 

Link to locked scientific article.
pdf of full text.

I’ve written an article for the Discover Magazine blog The Crux about mass hysteria and conversion disorder in light of the not-very-good-coverage given to the issue after a group of cheerleaders with unexplained neurological symptoms made the headlines.

The New York Times described the situation as a ‘nutty story’ and said hysteria is ‘not supposed to happen anymore’ which is insulting and wrong in equal measure.

Nature News described the situation as a ‘mystery US outbreak’ and managed to confusion conversion disorder with mass hysteria, generating a unfortunate mix of scaremongering and confusion.

So the article for Discover Magazine tracks the history of conversion disorder (the condition that the girls have actually been diagnosed with), what it actually means (neurological symptoms without neurological damage) and the science of how we can experience unusual effects like blindness, paralysis or, in this case, tics, without actually having a neurological disorder.

As Freud fell out of fashion, many people assumed that the concept of hysteria had gone with him, but this is not the case. Although his theory about hysteria being caused by the “unconscious repression of trauma” isn’t very popular among scientists, it’s a simple fact that patients can develop what seem like neurological disorders—such as paralysis, blindness, seizures, and tics—despite having a perfectly functioning nervous system. And despite popular claims that the condition is rare or “doesn’t happen any more,” it still commonly presents in neurological clinics. Numerous studies have found that up to one-third of patients who consult with neurologists typically have symptoms that are not fully explained by neurological damage.

 

Link to Discover Crux piece on ‘Cheerleader hysteria’.

Nature has a fantastic article about how our sense of being located in our bodies is being temporarily warped and distorted in the lab of neuroscientist Henrik Ehrsson.

We’ve covered some of Ehrsson’s striking studies before as he has managed, with surprisingly simple equipment, to induce out-of-body experiences, the sense of having a third arm and the illusion of having a tiny doll-like body – among many other distortions.

But Ehrsson’s unorthodox apparatus amount to more than cheap trickery. They are part of his quest to understand how people come to experience a sense of self, located within their own bodies. The feeling of body ownership is so ingrained that few people ever think about it — and those scientists and philosophers who do have assumed that it was unassailable.

“Descartes said that if there’s something you can be certain of in this world, it’s that your hand is your hand,” says Ehrsson. Yet Ehrsson’s illusions have shown that such certainties, built on a lifetime of experience, can be disrupted with just ten seconds of visual and tactile deception. This surprising malleability suggests that the brain continuously constructs its feeling of body ownership using information from the senses — a finding that has earned Ehrsson publications in Science and other top journals, along with the attention of other neuroscientists.

The article looks at what this body distorting illusions are telling us about how the brain makes sense of our bodies and how these discoveries could be applied to ‘locating’ us in false limbs or even remote control robots.

Also don’t miss the podcast where author Ed Yong talks about his trip to the lab to try out the illusions.
 

Link to Nature article ‘Out-of-body experience: Master of illusion’.