It is only briefly mentioned in the article, but as a child Hepburn was caught behind German lines in Nazi-occupied Netherlands. Food was scarce, and the Nazi occupiers were brutal.
That would scar anyone.
https://en.wikipedia.org/wiki/Audrey_Hepburn#1939%E2%80%931945:_Experiences_during_World_War_II
Some movie stars of that era were like Audrey and Gary Cooper ,known primarily from the roles they played in movies and in theatre, while other stars such as Katherine Hepburn and Elizabeth Taylor were known most from how they conducted their private lives.
Yep the “Hongerwinter” of 1944.