mood stabilizer
any of various drugs used in the treatment of cyclic mood disorders (bipolar disorders and cyclothymic disorder). Because they reduce the symptoms of mania or manic episodes, mood stabilizers are sometimes known as antimanic drugs. Lithium is usually the first-line medication for bipolar I disorder, but anticonvulsants, such as valproic acid, carbamazepine, and oxcarbazine, are becoming more commonly used for this condition and are now preferred for other cyclic disorders. The calcium-channel blocker verapamil is also being investigated as a mood stabilizer. Mood stabilizers are occasionally used in the management of severe affective lability found in some personality disorders (e.g., borderline personality disorder).