Memory surgery: common drug takes the panic out of traumatic memories

Memory-induced panic attacks can be absolutely crippling for sufferers of post-traumatic stress disorder (PTSD) - the suffocating, gripping fear associated with traumatic memories can destroy victims' careers, relationships and the normal functioning of their lives. But a team of Dutch clinical psychologists are developing an almost magical cure, using a single dose of a common and fairly harmless beta-blocking drug that seems to be able to separate the panic emotion from the factual elements of the memory - leaving patients with an apparently lasting ability to recall and talk about the traumatic incident without the usual devastating rush of fear.

Memories of extreme trauma seem to be formed in a different way to normal memories. As the brain reels with the stress of the initial incident, the rush of stress and fear hormones seem to cause a different type of memory encoding, which can resurface for years afterward as an intense emotional connection that floods the body whenever the memory is recalled. PTSD victims experience this in a very physical and terrifying fashion.

Breaking the cycle: reconsolidation

But it turns out that each time a memory is recalled and thought about, the brain actually re-stores it. It's at this crucial "reconsolidation" phase that the memory can be separated from the fight-or-flight hormone rush that is so debilitating for victims.

Merel Kindt and her team at the University of Amsterdam have been working to develop an understanding of how the common beta-blocker propranolol seems to be able to interrupt the stress hormone encoding as a memory is being reconsolidated - leaving the memory apparently unaltered but removing the panic response.

The most effective technique seems to be to give patients a dose of propranolol - commonly used to treat hypertension, angina and cardiac arrhythmia - then, as the drug takes effect, reactivating the memory, stress effects and all. When the memory is re-encoded, the beta-blocking action of propranolol seems to prevent the re-storage of the emotional stress portion of the memory.

Clinical testing

Kindt's team are clinically testing the drug using an induced panic reaction associated with spiders in test subjects. On day 1, subjects were repeatedly shown photos of spiders, and were given an "uncomfortable" electric shock.

On day 2, the subjects were given either propranolol or a placebo, and were then shown the same images. Both the control and experimental groups shows a physical stress and fear reaction to the photos.

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