What do lithium carbonate, carbamazepine (tegretol), and valproate (depakote) have in common?

All the mentioned drugs are mood-stabilizing drugs.

A mood stabilizer refers to a psychiatric pharmaceutical drug used in the treatment of mood disorders featured by sustained and intense mood shifts, usually borderline personality disorder, bipolar disorder type I or type II, and schizoaffective disorder.

The term mood stabilizer does not illustrate a mechanism, however, an effect. More accurate terminology is used to categorize these agents.