Feb. 16, 2009 -- A commonly used blood pressure medication may also help erase or subdue fearful memories, researchers report in the online edition of Nature Neuroscience.
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 and Memory
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 untouched.
Changes in Your Personal Identity
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 humanity."