Written by Aisha Saleem, Pharmacist and Health Writer at PharmaHealths.com
Last Updated: August 2026
Bipolar disorder is a lifelong condition involving cycles of mania or hypomania and depression. Most people need long-term medication to stay stable and prevent relapses. The term “mood stabilizer” is often used, but it covers more medications than most people realize, and not all of them work in the same way or target the same phase of bipolar disorder. This guide explains each major medication category clearly, including a 2023 safety update that every person taking valproate should know about.
What Counts as a Mood Stabilizer?
A mood stabilizer is any medication that reduces the frequency and severity of mood episodes without significantly worsening the opposite pole. In bipolar disorder, that means not triggering mania when treating depression, and not deepening depression when treating mania. Three categories of medication are used: lithium, anticonvulsants, and atypical antipsychotics. All three are used at different phases and often in combination.
Lithium: The Gold Standard
Lithium has been in clinical use for over 70 years and remains the most comprehensively evidenced mood stabiliser available. It is effective across both poles of bipolar disorder, reducing the frequency and severity of manic episodes and providing meaningful protection against bipolar depression. NICE Clinical Guideline CG185 recommends lithium as a first line long-term treatment option for bipolar disorder, with valproate as an alternative.
Its most clinically significant property is its effect on suicide risk. A systematic review and meta-analysis published in the BMJ found that lithium substantially reduces the risk of suicide and self-harm in people with mood disorders compared with placebo. It is the only mood stabiliser with robust, replicated data on this outcome, and this should carry real weight in treatment decisions.
The limitation of lithium is its narrow therapeutic window. The effective dose and the toxic dose are close, so regular blood level monitoring is essential. Long-term lithium use also requires periodic monitoring of thyroid and kidney function.
Anticonvulsants: Valproate, Carbamazepine, and Lamotrigine
Several anticonvulsant medications are used in bipolar disorder, each with a distinct profile.
Valproate (prescribed as valproic acid, sodium valproate, or semisodium valproate) is effective for acute mania and is used in maintenance treatment, particularly for rapid cycling bipolar disorder and mixed affective states. However, NICE CG185, updated in December 2023, introduced an important prescribing restriction: valproate should not be started for the first time in people under 55 years of age unless two specialists independently agree and document that there is no other effective and tolerated treatment. This restriction applies to all people under 55, regardless of sex, due to the significant risks of birth defects and neurodevelopmental harm in children exposed to valproate during pregnancy. If you are currently taking valproate, this update should have been discussed with you at your last medication review.
Carbamazepine is another anticonvulsant option for acute mania and maintenance, but it is less commonly used because it interacts with a large number of other medications and requires careful monitoring. It is also a strong enzyme inducer, which means it can reduce the effectiveness of medicines such as oral contraceptives and warfarin. It is typically considered when lithium and valproate are not tolerated or not sufficiently effective.
Lamotrigine has a fundamentally different profile. It is primarily effective for preventing bipolar depression rather than mania. NICE CG185 is explicit on this point: lamotrigine should not be offered to treat mania. It is a maintenance medication used to reduce the frequency of depressive episodes, and it requires very slow dose titration because abrupt or rapid increases carry a small but serious risk of Stevens Johnson syndrome, a severe skin reaction.
Atypical Antipsychotics in Bipolar Disorder
Atypical antipsychotics are widely used in bipolar disorder across all phases of treatment. The WHO mhGAP 2023 updated guidelines recommend oral antipsychotics including aripiprazole, haloperidol, olanzapine, paliperidone, and quetiapine as evidence-based options for bipolar mania, alongside mood stabilisers such as lithium, carbamazepine, and valproate.
Quetiapine has a particularly broad evidence base because it is effective in both the manic and depressive phases of bipolar disorder. Aripiprazole and risperidone are used primarily for mania. Olanzapine (in combination with fluoxetine has evidence for bipolar depression specifically.
The key monitoring concern with atypical antipsychotics is metabolic: weight gain, increased blood glucose, and lipid changes. Regular metabolic checks are essential, especially with olanzapine and quetiapine.
Acute Treatment vs Maintenance: Different Goals, Different Medications
One of the most important and least explained aspects of bipolar pharmacology is that the medication used to manage an acute episode is not always the same as the medication used to prevent the next one.
A review of bipolar disorder treatment published in The Lancet by Geddes and Miklowitz identifies this as a fundamental distinction in clinical practice: acute treatment aims to resolve the current episode as quickly and safely as possible, while maintenance treatment aims to reduce the frequency and severity of future episodes over the long term.
Antipsychotics work relatively quickly for acute mania, often within days to two weeks. Lithium typically takes several weeks to reach full therapeutic effect. Lamotrigine requires slow titration over months and is not suitable for acute use at all. This is why treatment plans often change after an episode settles, shifting from rapid control to long-term prevention.
What About Antidepressants?
Antidepressants require very careful consideration in bipolar disorder. In some people, standard antidepressants can trigger a switch into mania or hypomania, or accelerate mood cycling. For this reason, NICE CG185 advises that antidepressants should not be used as monotherapy in bipolar disorder and should only be considered alongside a mood stabiliser or antipsychotic, with close monitoring.
If you have ever been prescribed an antidepressant without a bipolar diagnosis but have a history of periods of elevated mood, reduced sleep need, or increased risk-taking, it is worth discussing that history explicitly with your prescriber.
Key Monitoring Requirements
Bipolar medications require more active monitoring than most other psychiatric medications. As a pharmacist, this is one of the areas I see most often underdiscussed with patients.
• Lithium requires blood lithium levels checked every 3 to 6 months once stable, and thyroid and kidney function checked at least annually.
• Valproate requires liver function tests at baseline and periodically, with weight monitoring and, where relevant, discussion of reproductive risks.
• Carbamazepine requires full blood count and liver function at baseline and periodically, with blood levels checked if toxicity is suspected.
• Atypical antipsychotics require weight, blood glucose, and lipids checked at baseline, at 3 months, and then annually.
• Missing monitoring appointments increases real clinical risk. These checks are essential for safe and effective treatment.
Conclusion
Bipolar disorder is complex and its medication reflects that complexity. There is no single best mood stabiliser. The right choice depends on your episode pattern, which phase of illness you are in, what monitoring is feasible, and your individual tolerance of side effects. The goal is not just symptom control, but long-term stability with the safest and most appropriate treatment plan. Understanding what each medication targets, how long it takes to work, and what monitoring it requires puts you in a better position to have informed conversations with your prescriber. The evidence base supporting these medications is strong and spans decades of clinical research.
Disclaimer
This article is for informational purposes only and does not constitute medical advice. Bipolar disorder is a serious medical condition requiring specialist management. Never start, stop, or adjust any medication without guidance from a qualified healthcare professional. If you are in crisis, please contact a mental health helpline or emergency service in your area.
References
• National Institute of Mental Health. Bipolar Disorder. https://www.nimh.nih.gov/health/topics/bipolar-disorder
• Cipriani A, Hawton K, Stockton S, Geddes JR. Lithium in the prevention of suicide in mood disorders: updated systematic review and meta-analysis. BMJ. 2013;346:f3646. https://www.bmj.com/content/346/bmj.f3646
• National Institute for Health and Care Excellence. Bipolar Disorder: Assessment and Management. NICE Clinical Guideline CG185. 2014, updated 2023. https://www.nice.org.uk/guidance/cg185
• World Health Organization. mhGAP Evidence Centre: Antipsychotics and Mood Stabilizers in Individuals with Bipolar Mania. 2023. https://www.who.int/teams/mental-health-and-substance-use/treatment-care/mental-health-gap-action-programme/evidence-centre/psychosis-and-bipolar-disorders/antipsychotics-and-mood-stabilizers-in-individuals-with-bipolar-mania
• Geddes JR, Miklowitz DJ. Treatment of bipolar disorder. The Lancet. 2013;381(9878):1672-1682. https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(13)60857-0/fulltext
