Stress is the largest source of aging. The more severe the stress the faster people age.

The most extreme case I saw was a former coworker. When we worked together we were both in our late 20's. She then went onto another job and we lost contact.

5 years later I ran into her at a meeting and was shocked. Unfortunately her younger son had died of cancer in the meantime and the stress had aged her 20+ years. She looked in her late 50's not mid 30's.