Which medication class is considered first-line mood stabilizer in bipolar disorder?

• A. Lithium
• B. Sertraline
• C. Olanzapine
• D. Haloperidol

Answer: (A)

Lithium stands as the first-line mood stabilizer in bipolar disorder because it has the strongest, longest-standing evidence for preventing manic and depressive episodes and for reducing suicide risk. It works across mood states and has a well-established role in long-term maintenance, which is why guidelines routinely favor it as initial therapy. Remember that it requires regular blood level monitoring due to a narrow therapeutic window and potential side effects on kidney and thyroid function, plus interactions with NSAIDs and certain other drugs. In contrast, a selective sertraline is an antidepressant and can precipitate mania if used alone, so it isn’t a mood stabilizer. Olanzapine and haloperidol are antipsychotics useful for acute mania or specific situations, but they’re not the standard first-line agents for ongoing mood stabilization.