Thank you for those biochem pathway pages, mrsd.

We've owned a lightbox for the past 6 yrs., but it's parked in my son's room. Without it, he's like a hibernating bear in the dark dreary months here in the PNW. Now that you mention the light, I'm wondering whether the last few times I tried the Sam-E, maybe it was in winter. I do know that I am quite sensitive to melatonin; even a fragment of tablet makes me sleepy, achy, and depressed.