For people suffering from posttraumatic stress disorder (PTSD), distressing memories repeat in an endless loop. Thus far, one of the best treatments found for PTSD is exposure therapy, in which suffers relive or re-visualize their traumas in a controlled environment until they are no longer haunted by them.
Unfortunately, this therapy helps only half of the patients that try it, Melissa Pandika writes for Ozy Magazine. And since 7.7 million Americans suffer from PTSD (according to the National Institutes of Health), many of them veterans (according to several studies, at least 20 percent of Iraq and Afghanistan veterans experience PTSD), researchers are looking for ways to make this treatment more effective.
MIT neuroscientists have high hopes for a new drug — CI-994 — which could strip the negative emotions out of traumatic memory.
Neuroscientist Li-Huei Tsai, who leads the MIT team conducting trials of the drug, discovered that a certain enzyme was present in large quantities in mice showing symptoms of dementia. She wondered if the same enzyme that causes mice to lose their memories could play a role in how traumatic memories are locked into place. She trained mice to fear a specific chamber of their enclosure by administering a shock to them when they entered. She reintroduced some mice to the chamber the next day, teaching them that it was now safe, and these mice no longer reacted in fear. The mice that weren’t reintroduced to that chamber until 30 days after they’d been shocked retained the fearful memory and could not be retrained. This situation might be analogous to a veteran who waits for months or years before seeking treatment for PTSD.
Next Tsai administered the CI-994 drug to the mice who had 30-day traumatic memories of the shock chamber. The CI-994 drug suppresses the dementia-associated enzyme she’d discovered earlier. After one treatment, the mice were no longer afraid. They retained all their other memories and the associated emotional responses to them except the traumatic one.
There’s still a long way to go before determining whether CI-994 can be effective in humans. The Navy is currently preparing a clinical trial of the drug. But if the drug proves promising, it might entice some of the estimated 50 percent of veteran PTSD sufferers who don’t seek treatment to give therapy a try.