Molecular space-filling model of valproic acid. Valproic acid (or valproate, VPA) is an anticonvulsant and mood-stabilising drug, and is used to treat epilepsy, seizures, migraines, bipolar disorder and depression. It is also being studied for use in neurodegenerative diseases, as an anti-cancer drug, and in the treatment of AIDS. Valproic acid is thought to work by increasing the concentration of the neurotransmitter GABA in the brain. The atoms are shown as colour-coded spheres: hydrogen (white), carbon (grey), and oxygen (red).