Why do some people develop Post-Traumatic Stress Disorder after experiencing trauma, while others do not? Though the topic of PTSD has been studied a lot, finding a group of people who all experienced the exact same trauma is usually not possible. Pinpointing why PTSD develops in certain individuals is, however, hard when everyone you're studying has been through different experiences.
Enter psychologist Margaret McKinnon from Canada, lead author of a new study that examines the link between memory processing styles and Post-Traumatic Stress Disorder, and survivor of a traumatic plane near-disaster in 2001.
'Imagine Your Worst Nightmare — That's What It Was Like'
McKinnon was about to start her honeymoon when Air Transat Flight 236 from Toronto to Lisbon when disaster struck. An incorrect hydraulic pump led to chafing between the fuel line and hydraulic line, a problem the pilots found out about after the plane had already dumped eight tons of fuel. When they tried to fix the problem by directing fuel from the other tank to the ruptured one, they had no choice but to alert the passengers they would be preparing for an ocean ditching.
“We were asked to put on our life jackets… the cabins depressurized, the oxygen masks came down… and several announcements were made that we would ditch into the ocean,” McKinnon told the press. She and her fellow passengers were prepared for ocean ditching and even counted down to impact, but the pilots eventually managed to land on a small island in the Azores instead of in the ocean. The crash landing left 18 crew and passengers injured, but all 306 people who were on the plane survived.
In other words, the near-disaster was absolutely PTSD material. Indeed, 50 percent of those on board did develop Post-Traumatic Stress Disorder. But why not the other half?
Today, McKinnon is a clinician-scientist at St Joseph's Healthcare Hamilton and associate co-chair of research in the Department of Psychiatry and Behavioral Neurosciences at McMaster University in Hamilton in Canada. She turned her worst nightmare into a fascinating study that should give us all a better idea about the nature of PTSD.
“We knew that it was going to be really a once-in-a-lifetime chance from a research perspective,” her co-author Brian Levine — senior scientist at Baycrest Health Services and a professor of psychology at the University of Toronto — said.
'Tremendously Enhanced Vivid Memories'
For the study, published in the journal Clinical Psychological Science, McKinnon recruited 15 other co-passengers. The researchers tested these passengers' memories by asking them to recall 9/11 — which happened just weeks later — and another neutral event from the same time period.
The study found that the passengers displayed "tremendously enhanced vivid memories" of the flight, something that's interesting when you consider the frequent claim that traumatic events are suppressed. The research team's most significant findings emerged when they compared participants' accuracy of recall with their chance of developing PTSD.
In case you're wondering what that means, they're talking about details that weren't related to the traumatic event itself — like their feelings at the time, or editorial statements. Levine said it's normal that people have different degrees of control over their memory, adding: "Some people have very efficient, special, targeted memory. Other people have less inhibition on their memory."
The team plans to follow-up on their findings by conducting brain imaging of some of the passengers, to find out which areas of the brain are linked to trauma.