Mood stabilizer to know.

• A. Lithium
• B. Lamotrigine
• C. Diazepam
• D. Quetiapine

Answer: (A)

Mood stabilization in bipolar disorder hinges on agents that provide durable control of mood swings, not just short-term calming. Lithium stands out because it has the strongest, longest‑standing evidence for both treating acute mania and preventing future manic and depressive episodes. It also lowers suicide risk, which is a crucial benefit in bipolar care. This broad, proven effectiveness is what makes it the mood stabilizer you’re expected to know well. The exact mechanism isn’t fully understood, but lithium is thought to modulate signaling pathways and neuronal plasticity in ways that help stabilize mood over time. Because it has a narrow therapeutic window, patients require regular blood level checks and monitoring of kidney and thyroid function, with common side effects like tremor, increased thirst and urination, and potential weight changes.

Lamotrigine is an anticonvulsant that's valuable, especially for bipolar depression and maintenance, but it isn’t as effective for acute mania. Diazepam is a benzodiazepine used for anxiety and agitation, not for long-term mood stabilization. Quetiapine, an antipsychotic, can help with mood symptoms in bipolar disorder but isn’t the classic mood stabilizer; it’s typically part of a broader treatment plan.