[Following a violent robbery, Joël] Coutu’s ordeal was just beginning. For years he would be tormented by violent nightmares, panic attacks brought on by the mere hint of aggression around him, and severe depression—signs of post-traumatic stress disorder (PTSD).
Then, one day in 2009, he saw an advertisement in a local newspaper for a trial of an experimental therapy run by Alain Brunet, a McGill University psychiatrist. Brunet suggested something radical: he wanted to erase portions of Coutu’s memory.
For decades scientists believed that long-term memories were immutable—unstable for a few hours and then etched into the brain for good. Research now suggests that recalling a memory causes it to revert temporarily to an insecure state, in which the recollection can be added to, modified, even erased.
“Imagine a high jumper who fell during the Olympics,” says neuroscientist Karim Nader of McGill. “They may have a lot of anxiety associated with jumping, and it could severely affect their future performance. If we can make these drugs work, you could help them, too—or anyone with anxiety that is proving a problem.”