This study will be conducted in two phases. During Phase I, participants will stop all medications for at least 1 week. A psychiatric and medical examination will be conducted. During Phase II, participants will be randomly assigned to receive either Novasoy (Registered Trademark) or a placebo (an inactive pill) for 8 weeks. Participants who do not respond to treatment after 5 weeks will be given a higher dose of their assigned medication. After the 8-week period, participants will be monitored for up to 3 months before being referred back to their clinician for further treatment.