Lithium Versus Divalproex for Treating Pediatric Bipolar Disorder

Primary Aim: To compare the efficacy of lithium (LI), divalproex (DVP), and placebo (PBO) in the acute phase treatment of symptomatic bipolar I disorder, mixed or manic episode, in children and adolescents. Our hypothesis is that differential efficacy will be observed with the following predicted order of response: divalproex (DVP) = lithium (LI) \> placebo (PBO). Secondary Aims: 1. To collect systematic safety data on the incidence of weight gain and the development of insulin resistance and hyperandrogenism in bipolar adolescent females treated with LI, DVP, or LI + DVP. 2. To collect data on possible predictors of acute treatment response to the two active treatments. 3. To provide descriptive information on the stability of acute phase response to monotherapy with either LI or DVP over 6 months of continuation phase treatment. 4. To develop safety and efficacy data about the use of stimulant medications in these subject while treated with a mood stabilizer.