Suppose you could erase bad memories from your mind. Suppose, as in a recent movie, your brain could be wiped clean of sad and traumatic thoughts.
That is science fiction. But real-world scientists are working on the next best thing. They have been testing a pill that, when given after a traumatic event like rape, may make the resulting memories less painful and intense.
Will it work? It is too soon to say. Still, it is not far-fetched to think that this drug someday might be passed out along with blankets and food at emergency shelters after disasters like the tsunami or Hurricane Katrina.
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... post-traumatic stress disorder, or PTSD, a problem first recognized in Vietnam War veterans. Only 14 percent to 24 percent of trauma victims experience long-term PTSD, but sufferers have flashbacks and physical symptoms that make them feel as if they are reliving the trauma years after it occurred.
Scientists think it happens because the brain goes haywire during and right after a strongly emotional event, pouring out stress hormones that help store these memories in a different way than normal ones are preserved.
Taking a drug to tamp down these chemicals might blunt memory formation and prevent PTSD, they theorize.
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Memories, painful or sweet, don't form instantly after an event but congeal over time. Like slowly hardening cement, there is a window of opportunity when they are shapable.
During stress, the body pours out adrenaline and other "fight or flight" hormones that help write memories into the "hard drive" of the brain, McGaugh and Cahill showed.
Propranolol can blunt this. It is in a class of drugs called beta blockers and is the one most able to cross the blood-brain barrier and get to where stress hormones are wreaking havoc. It already is widely used to treat high blood pressure and is being tested for stage fright.
Dr. Roger Pitman, a Harvard University psychiatrist, did a pilot study to see whether it could prevent symptoms of PTSD. He gave 10 days of either the drug or dummy pills to accident and rape victims who came to the Massachusetts General Hospital emergency room.
In follow-up visits three months later, the patients listened to tapes describing their traumatic events as researchers measured their heart rates, palm sweating and forehead muscle tension.
The eight who had taken propranolol had fewer stress symptoms than the 14 who received dummy pills, but the differences in the frequency of symptoms were so small they might have occurred by chance — a problem with such tiny experiments.
Still, "this was the first study to show that PTSD could be prevented," McGaugh said, and enough to convince the federal government to fund a larger one that Pitman is doing now.
Meanwhile, another study on assault and accident victims in France confirmed that propranolol might prevent PTSD symptoms.
One of those researchers, Brunet, now has teamed with Pitman on the boldest experiment yet — trying to cure longtime PTSD sufferers.
"We are trying to reopen the window of opportunity to modulate the traumatic memory," Pitman said.
The experiments are being done in Montreal and involve people traumatized as long as 20 or 30 years ago by child abuse, sexual assault or a serious accident.
"It's amazing how a traumatic memory can remain very much alive. It doesn't behave like a regular memory. The memory doesn't decay," Brunet said.
To try to make it decay, researchers ask people to describe the trauma as vividly as they can, bringing on physical symptoms like racing hearts, then give them propranolol to blunt "restorage" of the memory. As much as three months later, the single dose appears to be preventing PTSD symptoms, Brunet said.
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Practical matters may limit propranolol's usefulness. It must be given within a day or two of trauma to prevent PTSD.
How long any benefits from the drug will last is another issue. McGaugh said some animal research suggests that memory eventually recovers after being squelched for a while by the drug.
Overtreatment also is a concern. Because more than three-quarters of trauma victims don't have long-term problems, most don't need medication.
