I find studies about light therapy draw my attention every time as I am so sensitive to needing light for my emotional well being.
This particular article mentions the increased melatonin production and the resultant decrease in cortisol levels."The light-therapy group also showed an increased level in the evening of the sleep-promoting hormone, melatonin, and a decrease in levels of cortisol, the stress hormone."
That research fits nicely with the articles sited in the new thread by imark3000 about the ratio of dopamine to acetylcholine. One of those articles states
"Melatonin also can decrease cortisol levels (adrenaline), which can be high from chronic stress. Decreasing excess cortisol levels can be helpful in decreasing the amount of dopamine depleted to make adrenaline hormones."
Logically, Vitamin D and all the recent hub-bub and research on it, must also be similarly involved.
Out into the sunshine I will be going! And I am going to try to be more faithful in taking 3 mg. of melatonin before bed.