A possible "vaccine" for post-traumatic stress disorder might help protect soldiers in battle.

Scientists at the Massachusetts Institute of Technology in Cambridge claim the ghrelin hormone produced during stressful situations makes the brain vulnerable to PTSD. They say by blocking ghrelin, they might be able to prevent the formation of PTSD after traumatic events.

PTSD has affected nearly a quarter-million service members who have fought in Iraq and Afghanistan since 2001.

[Metro Networks]