What is the substance used to treat the manic stage of manic-depressive illness?

Lithium is the primary substance used to treat the manic stage of manic-depressive illness, also known as Bipolar disorder. It helps stabilize mood and reduce the intensity of manic episodes. Other medications, such as certain anticonvulsants and atypical antipsychotics, may also be used in conjunction or as alternatives. Regular monitoring is essential due to potential side effects and the need for dosage adjustments.