Kathleen Logue was waiting at a traffic light when two men smashed her car's side window, pointed a gun at her head and ordered her to drive. For hours, Logue fought off her attackers' attempts to rape her, and finally she escaped. But for years afterward, she was tormented by memories of that terrifying day.
So years later, after a speeding bicycle messenger knocked the Boston paralegal onto the pavement in front of oncoming traffic, Logue jumped at a chance to try something that might prevent her from being haunted by her latest ordeal.
"I didn't want to suffer years and years of cold sweats and nightmares and not being able to function again," Logue said. "I was prone to it because I had suffered post-traumatic stress from being carjacked. I didn't want to go through that again."
Logue volunteered for an experiment designed to test whether taking a pill immediately after a terrorizing experience might reduce the risk of post-traumatic stress disorder (PTSD). The study is part of a promising but controversial field of research seeking to alter, or possibly erase, the impact of painful memories -- a concept dubbed "therapeutic forgetting" by some and taken to science fiction extremes in films such as this summer's "Eternal Sunshine of the Spotless Mind."
Proponents say it could lead to pills that prevent or treat PTSD in soldiers coping with the horrors of battle, torture victims recovering from brutalization, survivors who fled the World Trade Center on Sept. 11, 2001, and other victims of severe, psychologically devastating experiences.
"Some memories can be very disruptive. They come back to you when you don't want to have them -- in a daydream or nightmare or flashbacks -- and are usually accompanied by very painful emotions," said Roger K. Pitman, a professor of psychiatry at Harvard Medical School who is studying the approach. "This could relieve a lot of that suffering."
Skeptics, however, argue that tinkering with memories treads into dangerous territory because memories are part of the very essence of a person's identity, as well as crucial threads in the fabric of society that help humanity avoid the mistakes of the past.
"All of us can think of traumatic events in our lives that were horrible at the time but made us who we are. I'm not sure we'd want to wipe those memories out," said Rebecca S. Dresser, a medical ethicist at Washington University in St. Louis who serves on the President's Council on Bioethics, which condemned the research last year. "We don't have an omniscient view of what's best for the world."
Some fear anything designed for those severely disabled by psychic damage will eventually end up being used far more casually -- to, perhaps, forget a bad date or a lousy day at work.
"You can easily imagine a scenario of 'I was embarrassed at my boss's party last night, and I want to take something to forget it so I can have more confidence when I go into the office tomorrow,' " said David Magnus, co-director of Stanford University's Center for Biomedical Ethics. "It's not hard to imagine that it will end up being used much more broadly."
So far, only a handful of small studies have been conducted in people in the United States and France, most testing a drug called propranolol, which blocks the action of stress hormones that etch memories in the brain. The results suggest drugs may be able to prevent traumatic memories from being stored with such disturbing intensity in the first place, or perhaps deaden effects of old memories if taken shortly after they have been reawakened. The results have been promising enough that researchers are planning larger studies in several countries, including the United States, Canada, France and Israel, testing propranolol and other drugs, including the active components of marijuana.
"You always have the ability to misuse science," said Joseph E. LeDoux, a New York University memory researcher planning one of the studies. "But this isn't going to be radical surgery on memory. All we'd like to do is help people have better control of memories they want or prevent intrusive memories from coming into their minds when they don't want them."
The ability to manipulate memory has long been the stuff of science fiction, inspiring fears of government mind control and films such as the 1962 classic "The Manchurian Candidate." No one is anywhere near having the power to extract the memory of a love affair or implant complex new memories, as depicted in "Eternal Sunshine" and a 2004 "Manchurian Candidate" remake.
But scientists have started taking the first tentative steps toward developing treatments based on new insights into why emotionally charged events -- whether it be President John F. Kennedy's assassination, Sept. 11 or a first kiss -- create such indelible memories.