Dutch scientists claim to have shown that the beta-blocker propranolol can "erase" unpleasant memories - a discovery which "opens up new avenues for providing a long-term cure for patients with emotional disorders".
Professor Merel Kindt and her team from the University of Amsterdam first subjected human volunteers to a "fear acquisition" process - that of causing them to associate pictures of spiders with a mild electric shock delivered to their wrists.
A day later, the volunteers were divided into two groups, once of which was given propranolol and the other placebo pills. All then underwent "memory reactivation" by enjoying the spider pictures for a second time. The team measured the "conditioned fear response" to the images by testing how the subjects reacted to a sudden loud noise - indicated by their "eyeblink startle reflex", aka "startle response".
The upshot of the testing (explained in further detail here at Nature Neuroscience) was that those who'd taken propranolol were simply less afraid than those who hadn't.
The team wrote: "Millions of people suffer from emotional disorders and the relapse of fear, even after successful treatment. Our findings may have important implications for the understanding and treatment of persistent and self-perpetuating memories in individuals suffering from emotional disorders."
However, professor Neil Burgess of the Institute of Cognitive Neuroscience said the research "merely demonstrates that the beta blockers reduce a person's startle response, breaking the association of the spider to these unconscious responses", as the BBC puts it.
Dr Daniel Sokol, lecturer in Medical Ethics at the University of London, expressed ethical concerns, explaining: "Removing bad memories is not like removing a wart or a mole. 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."
One such possible knock-on effect was proposed by John Harris, Professor of Bioethics at the University of Manchester, who said: "An interesting complexity is the possibility that victims, say of violence, might wish to erase the painful memory and with it their ability to give evidence against assailants."
There's supplementary information on the Dutch findings here. ®
Propranolol is used to treat "tremors, angina (chest pain), hypertension (high blood pressure), heart rhythm disorders, and other heart or circulatory conditions". There's more on the drug here.