Pharmacogenomics of Mood Stabilizer Response in Bipolar Disorder (PGBD)

All subjects meeting study inclusion criteria will be started on lithium. Those that fail lithium will be crossed over to valproate (VPA). Those that also fail VPA will be again crossed-over to a standardized treatment as usual (TAU) arm. Subjects who are eligible for the study must be at least 18 years of age and have been diagnosed or are thought to have bipolar I disorder with at least one episode of mood instability in the last 12 months. They must also be eligible to take lithium and, if female and of child bearing age, agree to use adequate birth control methods and to inform their doctor of their plans to become pregnant.