Beta-blockers erase emotion of fearful memories
Memory remains, but feeling of fear is less or gone, shows experimental
study in people
By Solmaz Barazesh Web edition :
The first experimental study in humans connecting beta-blockers and
memory suggests these drugs, usually taken to treat heart conditions, can also
wipe away the emotions associated with frightening memories, according to a
study published online February 15 in Nature Neuroscience. The power
of such memories could be dampened when a person
thinks about the traumatic events after taking the drugs, the scientists say.
Clinical psychologist Merel Kindt of the
“Kindt’s work confirms our clinical results
and goes further by showing beta-blockers also have this effect” on people who
had no previous history of mental health issues, comments Alain Brunet,
psychiatrist at the Douglas Mental Health University Institute at McGill
University in Montreal and a coauthor of the PTSD study.
Kindt and her colleagues showed subjects a
photograph of a spider, which was accompanied by an
electric shock, conditioning the participants to have a fearful memory of the
image. Later, some participants were given a
beta-blocker drug, propranolol, and others were given
a placebo before being exposed to the image again. The beta-blocker group’s
fear response was greatly reduced or even eliminated when the subjects were shown the spider photograph 24 hours after taking the
drugs. “The people did not forget seeing the photograph of the spider,” Kindt says. ”But the fear associated with the image was
erased.”
The researchers think beta-blockers work by changing the way the
frightening memories are stored. Each time a memory is
recalled it changes a little, and the new version is recorded in the
long-term memory stash via brain chemical fluctuations in a process called
reconsolidation. The beta-blockers could interfere with the brain chemicals,
blocking reconsolidation of the emotional component of the memory, but leaving
the rest of the memory intact, the scientists suggest.
If beta-blocker treatment were applied to
people with anxiety disorders, “People would remember going through the trauma,
but the emotional intensity would be dulled,” comments Karim
Nader, behavioral neurobiologist at
Beta-blockers wouldn’t stop reconsolidation of
only frightening memories, the researchers say. “It’s likely that any emotional
memory, happy or sad, recalled after taking the drug would be dulled,” Kindt speculates. But patients
with fear-based anxiety disorders probably aren’t thinking about the happy
moments of their lives; they are obsessed with the traumatic moments, the
scientists say.
Before beta-blockers can be considered a
widespread treatment for anxiety disorders, the long-term effects of the drugs
on memory must be assessed. But the drugs are
relatively benign and already widely prescribed for other conditions, the
researchers point out.
“Beta-blockers make the traumatic memories easier to deal with,” Nader says. “People can begin to talk about the traumatic
event, and can even move on.”
Origin, Science News: http://www.sciencenews.org/view/generic/id/40928/title/Beta-blockers_erase_emotion_of_fearful_memories