Pill could erase painful memories

10 juni 2011

What if you could take a pill and erase painful memories? Most of us would probably choose not to lose parts of our past, but for those with post-traumatic stress disorder, such a pill might bring welcome relief.

In a study that sounds very much like a scene from the movie “Eternal Sunshine of the Spotless Mind,” researchers have shown that the right medication might actually help rub out wrenching remembrances.

For the new study, researchers rounded up 33 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. “It’s not fun to watch,” she says. “It induces a lot of emotion.”

Before the video, Marin had instructed the volunteers to watch and listen very carefully to the presentation. Afterwards, she and her colleagues collected saliva samples to measure levels of the stress hormone, cortisol. Then the 33 were sent on their way.

Three days later, the study volunteers were brought back in to the lab. Some were given a placebo, while the rest were given one of two doses of a drug that knocks back the amount of cortisol coursing through the body.

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 — even after it’s already been created and stashed away in the brain.

When Marin asked the volunteers to try to recall the video presentation, those who were given the cortisol-damping drug had a harder time recalling the more wrenching details. The higher the dose, the harder it was for them to remember.

Four days later the volunteers were asked to once again come back to the lab. Surprisingly, the drug’s impact on memory was still apparent: volunteers who took it still had trouble recalling the emotionally charged scenes.

Marin hopes that the study, published in the August issue of the Journal of Clinical Endocrinology & Metabolism, might one day help people suffering from PTSD. She suspects that, in the right setting, the drug might help diminish the power of the traumatic event that kicked off the condition. The idea is that a patient would review the event with a psychotherapist after having taken the drug.

One of the most intriguing findings of the study is the fact that memories aren’t quite as indelible as we like to think. Each time we review them in our minds, there seems to be a chance for editing to occur, Marin says.

And that might lead to other interesting lines of research. “It might be that we can actually change them and create false memories,” she explains. “It’s a question that should be investigated. Using this paradigm, can memories still change once they’re formed?

By Linda Carroll, msnbc.com contributor​

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