A moo stabilizer is a psychiatric medication used to treat mood disorders characterized by intense and sustained mood shifts, which is not the same as "feeling good one minute and then bad the next." The most common is bipolar disorder, where mood stabilizers suppress swings between mania and depression, and these drugs are also used in borderline personality disorder. Most mood stabilizers are anticonvulsants, with the important exception of lithium, which is the oldest and best known mood stabilizing drug.