PLASMA GABA PREDICTS ACUTE RESPONSE TO DIVALPROEX IN MANIA

Bipolar I, manic phase inpatients were treated with divalproex sodium, lithium, or placebo in a previously reported parallel group multicent er, double-blind, randomized controlled acute phase treatment trial. P lasma concentrations of gamma aminobutyric acid (GABA) were measured b efore and after treatment. Higher pretreatment plasma GABA levels were significantly (p = .04) related to a better clinical response to diva lproex (n = 19). Pretreatment plasma GABA levels did not correlate wit h response to either lithium (n = 13) or placebo (n = 31). Following t reatment with divalproex sodium, plasma GABA levels decreased signific antly (p < .05), compared to placebo. Pretreatment plasma GABA levels were not related to overall severity of manic symptoms. Plasma GABA ma y predict response to pharmacologic agents acting on the GABA system.