Problem:
(Exogenous) melatonin is administered at night for treatment of circadian rhythm disorders, but melatonin taken during the day is linked with depression.
I would like to know if high blood levels of (endogenous) melatonin (at a steady state, throughout the day) might be linked with mood or sleep disorders (or have any effect at all), or if the body's response to melatonin adjusts accordingly.Explain it in detail.