So the idea behind beta blockers for preventing PTSD is that if you can prevent the body's stress system from reacting strongly to a trauma, you might be able to reduce the brain's fear and horror response.

CNN: Have you heard of a heart drug that also helps PTSD?

Here's the thing: if the Greek government were to miss a payment on a bond as it fell due, the immediate impact on the finances of the Greek government would be considerably less than the trauma that such a default would cause for the international banking system.

BBC: Is a Greek default so bad for Greece?