High dose Vitamin C defiintely up to two weeks before, low dose, I woulnt worry about it to much just avoid it on the day of the test..
the antidepressant you are will have a direct effect on cortisol, but this needs to be slowly weaned over a long time, so your ASI test will be inaccurate unfortunately. If you still want to go head, stop it just for the day, you wont go into withdrawals in a short space of time, but your endocrine system will be less stimulated by the chemical when the test is being done..