I have written before about the possible use of propranolol to dampen traumatic memories (see here). The initial studies tested the effects of propranolol on memories of recent events (i.e., it was thought that propranolol had to be taken within about six hours of the traumatic event in order to ease the emotional sting of a memory.) The jury is still out whether propranolol indeed has such effects.
Meanwhile, researchers are already testing whether propranolol can affect the quality of memories from the more distant past. For example, can a subject take propranolol while recalling traumatic memories from many years ago, in hopes that the memories will reconsolidate with less emotional valence? A recent small study by Brunet et al. suggests that it might. So far, I've only seen the following abstract:
The beta-adrenergic blocker propranolol given within hours of a psychologically traumatic event reduces physiologic responses during subsequent mental imagery of the event. Here we tested the effect of propranolol given after the retrieval of memories of past traumatic events. Subjects with chronic post-traumatic stress disorder described their traumatic event during a script preparation session and then received a one-day dose of propranolol (n=9) or placebo (n=10), randomized and double-blind. A week later, they engaged in script-driven mental imagery of their traumatic event while heart rate, skin conductance, and left corrugator electromyogram were measured. Physiologic responses were significantly smaller in the subjects who had received post-reactivation propranolol a week earlier. Propranolol given after reactivation of the memory of a past traumatic event reduces physiologic responding during subsequent mental imagery of the event in a similar manner to propranolol given shortly after the occurrence of a traumatic event.
Here's the optimistic take on this research from BBC news:
The researchers treated 19 crash or rape victims for 10 days with a drug, or a placebo.
The volunteers were asked to recall their memories of a traumatic event that had happened 10 years earlier.
A week later the researchers found that those people who were given a shot of propranolol showed fewer signs of stress, such as raised heart rate, when recalling their trauma.
The researchers believe that memories are initially stored in the brain in a malleable, fluid state before becoming hard-wired into the circuitry.
Then, when they are recalled, they once again become fluid - and capable of being altered.
They believe propranolol disrupts the biochemical pathways that allow a memory to "harden" after it has been recalled.
(Hat tip: Mind Hacks)
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