Patients are assigned randomly (like tossing a coin) to receive St. John's wort, Sertraline (Zoloft), or a placebo (sugar pill) for 8 weeks. This is a double-blind study, meaning neither the patient nor the doctor will know which treatment is being assigned. Patients who respond well to the treatment will continue on the assigned treatment for an additional 4 months. Patients will have regular follow-up visits to monitor their symptoms and any side effects they experience.