Still, Roger Pitman, a psychiatrist at the MGH and professor of psychiatry at the Harvard Medical School, was encouraged that the physical signs of PTSD appeared to be blocked by propranolol, and he has launched a larger study of individuals who come to the emergency room after trauma. Only a few studies have been attempted, says Pitman, largely because it’s difficult to recruit subjects within minutes or hours of a horrible event. A French trial showed that propranolol reduced PTSD symptoms, but it lacked a control group, and Pitman surmises that those who agreed to take the drug may have done well after trauma regardless of treatment. Another study, at the Veterans Administration Hospital in San Diego, found no positive effects of propranolol on PTSD, but Pitman thinks that may have been because the drug was given too late, as long as 24 hours after an event. “Memory consolidation may happen within as few as 30 minutes,” he says.
And there’s the rub, of course. Getting immediate treatment for someone who has been wounded on a battlefield or almost killed in a five-car pileup may be almost impossible. Even if a quick dose of a beta-blocker were available, who should get it? There are no definitive risk factors to identify those most likely to suffer PTSD, which afflicts just 20% of those who experience trauma. Moreover, although propranolol is considered relatively safe, with millions of people taking it for hypertension—and actors and musicians often using it to ward off stage fright—simply giving it to everyone might expose them to side effects (such as aggravated asthma). The best way to give propranolol in the emergency room, according to Pitman, is for doctors to know who is at high risk for developing PTSD and which of those individuals will respond favorably to propranolol—neither of which is currently possible. For effective treatment, a different approach was needed.
In the late 1990s, Karim Nader, professor of psychology at McGill University, was casting about for a research project. Listening to a talk on memory consolidation, he had what seemed like a bizarre idea—that perhaps when a memory is retrieved, it has to undergo the same process of consolidation in the brain that it underwent when the event first occurred.
Nader didn’t know it then, but, in fact, researchers in the 1960s had done experiments with rats suggesting that reconsolidation is a real phenomenon. Four decades ago, prominent memory scientists argued against the idea, and when Nader mentioned his idea to his mentor, Joseph LeDoux, professor of neuroscience and psychology at New York University and director of the university’s Center for the Neuroscience of Fear and Anxiety, LeDoux told him not to waste his time. “There was 40 years of research that said once a memory is consolidated it doesn’t become unstable again,” LeDoux says.
Still, Nader persisted, and reconsolidation, though still controversial, has become one of the hottest topics in memory research. It could have particular applications in treating PTSD, possibly enabling a kind of therapeutic forgetting to take place long after a memory has presumably become permanent and symptoms of PTSD have already appeared.
Nader hypothesized that because a memory can be edited—so that you remember things your way, and not necessarily how they happened—it must first enter a vulnerable state before it’s restored to long-term memory. Imagine that each time you recall an event, you’re taking down a box from a shelf and opening it. Then, when you’re finished, you stow it away again. Nader thought that while the box was open, it might be possible to alter the memory.
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