Okay, so here is how the research went down with a relatively small sized sample group in Montreal, Canada. Researchers gathered university students and asked them to watch a video presentation that told the story of a little girl who has a horrible accident while visiting with her grandparents. While the girl and her grandfather are constructing a birdhouse, one of the little girl's hands gets caught in a saw. One of the pictures shown to the study volunteers is of her mangled hand.
Though the girl's hand is eventually saved at the hospital and the story ends fine, the presentation is tough to sit through and tends to cause viewers emotional distress, explains the study's lead author Marie-France Marin, a doctoral student at The Center for Studies on Human Stress at the University of Montreal.
Before the viewing of the short, saliva samples were collected from the subjects to measure levels of the stress hormone, cortisol. Although stress isn't the only reason that cortisol is secreted into the bloodstream, it has been termed "the stress hormone" because it's also secreted in higher levels during the body's "fight or flight" response to stress, and is responsible for several stress-related changes in the body.
Three days later, the study volunteers were brought back in and were given a placebo, while the rest were given one of two doses of a drug that knocks back the amount of cortisol in the bloodstream.
The theory is that cortisol is somehow involved in preserving memories, especially emotionally charged ones, Marin explains. Cut back on cortisol and maybe you'll be able to mess with a memory. When Marin asked the volunteers to try to recall the video presentation, those who were given the cortisol mellowing drug had a harder time recalling the more wrenching details. The higher the dose, the harder it was for them to remember.
While cortisol is an important and helpful part of the body's response to stress, it's important that the body's relaxation response is activated so the body's functions can return to normal following a stressful event. Unfortunately, in our current high-stress culture, the body's stress response is activated so often that the body doesn't always have a chance to return to normal, resulting in a state of chronic stress.
Marin hopes that these findings might one day help people suffering from , post-traumatic stress disorder or PTSD. The cortisol blocker may help diminish the power of the traumatic event that kicked off the condition.
"It might be that we can actually change them (memories) and create false memories. It's a question that should be investigated. Using this paradigm, can memories still change once they're formed? If they can, that raises some ethical questions when it comes to legal testimony."
Source: The Journal of Clinical Endocrinology & Metabolism