Drug Tweaks Epigenome to Erase Fear Memories

A hurricane, a car accident, a roadside bomb, a rape — extreme stress is more common than you might think, with an estimated 50 to 60 percent of Americans experiencing it at some point in their lives. About 8 percent of that group will be diagnosed with post-traumatic stress disorder, or PTSD. They will have flashbacks and nightmares. They will feel amped up, with nerves on a permanent state of high alert. They won’t be able to forget.One of the only effective treatments for PTSD is ‘exposure therapy,’ in which people are repeatedly exposed to their fear — such as a painful memory — in a safe context. This treatment works partly because of how our brain encodes memories. Whenever we actively recall a memory, it transforms into a pliable molecular state and becomes vulnerable to modification.About half of people who get exposure therapy for PTSD get better. But that still leaves a lot of people who don’t. A mouse study published last week in Cell throws the spotlight on a drug that acts in concert with exposure therapy to help extinguish fear memories. The drug works by changing the epigenome, the chemical markers that attach to DNA and can turn genes on and off.Read more at...Only Human, January 2014.