The U.S. Food and Drug Administration (FDA) has approved Lamictal as a "maintenance treatment" for bipolar disorder, a mental illness. The objective is to slow the mood changes of this disorder.

Often doctors find that medicines are useful for more than one purpose. It is legal to prescribe medicines for "off-label uses" even though the FDA has not formally approved such use. Common off-label uses of Lamictal include:

• certain kinds of pain directly involving nerves
• a type of facial pain called trigeminal neuralgia