system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5 Why do people seem to age so incredibly fast after a traumatic experience?

For example a woman I know seemed to have aged at least ten years in a very short time after her grandchild died in an accident.
gpt
Cortisol, known as the "stress hormone", causes all sorts of inflammatory responses throughout the body, which contribute to the aging effect. When you add in the psychological implications of the trauma (depression, guilt, etc) that change the person's affect, the combined result is that the person seems ages older than they were.