I was caffine free for four years. But as a rapid cycling manic-depressive 9baby brain strokes as well), even maxed out on two anti-depressants, and other medications, I remained depressed without constant caffine intake.(I drank soda from age four through to adulthood, almost exclusively, I think I am hard wired.)
I have found that Liptons gallon size Ice Tea, tea bags soaking in a 3 liter jar in the refidgerator with seven bags of sweet-&-low (saccuran) added afterwards. Gives me the alertness, lack of depressive symptoms and without the mood peaking associated with sodas. I drink about 5 liters a day of the tea.
Thats my experience. Now I have no experience with ginsing or ginko-balboa. And especially would like to hear some opinions as to how they and or caffine relate to photoreading in your experiences.