Depression and PTSD are chronic, often lifelong, clinical diseases. They also increase the risk of substance abuse, homelessness, heart disease, Alzheimer's, suicide. The global cost of depression alone is over three trillion dollars per year. But now, imagine a scenario where we know someone is predictively at high risk for exposure to extreme stress. Say, a red cross volunteer going into an earthquake zone. In addition to the typhoid vaccine, we could give her a pill or an injection of a resilience enhancer before she leaves. So when she is held at gunpoint by looters or worse, she would at least be protected against developing depression or PTSD after the fact. It won't prevent her from experiencing the stress, but it will allow her to recover from it. And that's what's revolutionary here. By increasing resiliency, we can dramatically reduce her susceptibility to depression and PTSD, possibly saving her from losing her job, her home, her family or even her life.