What you can not see

When I see this photo I can see how sad this girl is.
1) The first thing that comes to mind is pain, and what caused it.

2) She is carrying a heavy load. Something has happened to create such a level of sadness. What ever has happened has made a impact in her life that will follow her until she leaves this earth.
So I know what happened but from looking at this picture can you figure out the cause, that created the effect?