WebMD Medical News
Louise Chang, MD
Feb. 16, 2009 -- A commonly used blood pressure medication may also help
erase or subdue fearful memories, researchers report in the online edition of
Scientists at the University of Amsterdam have discovered that the drug
propranolol, a beta-blocker, prevents the return of unpleasant memories. The
finding could lead to a new realm of treatments for patients with posttraumatic
stress and other emotional disorders.
Animal research has shown that fearful memories are not necessarily
permanent, but rather that they can change when remembered. In animals, this
process, called reconsolidation, appears vulnerable to beta-blockers. Merel
Kindt and colleagues wanted to find out if the same was true in people. In
their study, 60 undergraduate students aged 18 to 28 viewed fear-related images
on a computer and learned to link pictures of spiders with a mild shock to the
hand, which created a fearful memory.
After a 24-hour break, the researchers randomly gave each participant either
40 milligrams of propranolol or a placebo (dummy pill). An hour and a half
later, they asked the students to view the spider pictures again and to
remember what they had learned the day before.
The students who received the beta-blocker propranolol showed no return of
fear when viewing the spider pictures, a finding that suggests the entire fear
memory was removed.
Propranolol targets nerve receptors in the part of the brain called the
amygdala while it is processing emotional information, according to background
information in the journal article. The amygdala helps you learn and respond to
fear, create memories, and perceive how you and other's feel. Some think that
the use of beta-blockers during reactivation of fearful thoughts may cause the
breakdown of the unpleasant memory in the amygdala while leaving other memories
However, the possibility of eliminating unpleasant memories isn't without
risk, some medical ethics experts say.
"Removing bad memories is not like removing a wart or a mole,"
Daniel Sokol, lecturer in medical ethics at St George’s, University of
London, says in a statement. "It will change our personal identity since
who we are is linked to our memories. It may perhaps be beneficial in some
cases, but before eradicating memories, we must reflect on the knock-on effects
that this will have on individuals, society, and our sense of
SOURCES:Kindt, M. Nature Neuroscience, published online, February 2009.News release, Nature Neuroscience.News release, The Science Media Centre (SMC).
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