[agumonkey]

I didn't mean to imply mental problems, but emotion can trigger imbalances in how your system produce and regulate this molecules.

[dekhn]

that's not psychology, that's neuroscience, and while generally observed, the phenomenon you describe isnt understood.

[DataWorker]

Stress isn't psychological? Think about what you are saying!

[dekhn]

Strictly speaking, from a conventional mainstream scientific view, stress is physiological. Psychology is a subset of physiology (unless you believe minds are aphysical). The "stress" that you feel in your head when you're stressed is only part of a larger, bodywide physical response.