 Phase 2B is active and currently recruiting participants. This is a randomized, placebo controlled study of folate supplementation. Participants in phase 2B will attend 6 study visits over the course of 6 months. At the first study visit they will be randomized to either folic acid 5mg daily for 4 months or placebo. This 4 month period is followed by a 2 month follow up visit, when no supplementation is given. At each study visit, participants will be asked about thoughts, illness, functioning, diet, medication side effects, recent medication history, smoking history, alcohol intake, and exercise habits. On the first and last visits, participants will undergo additional tests of genetics, blood hormone levels, and blood vessel functioning, and additional measurements will be made of height, weight, vital signs, and body size. 