The study consists of two phases, each lasting a total of four weeks (8 weeks total), with visits at the DCRP every 10 days. If the subject is eligible, they will be asked to return two weeks later for a baseline visit, when they will be randomly assigned, like a flip of a coin, to one of three treatment groups: a) drug/drug, b) placebo/drug, c) placebo/placebo (a placebo is a pill that looks like a study drug but contains no active medication). They will have a greater than 50% chance of receiving active medication (Deplin) at some point in the 8 week study.