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This is a clinician-written, evidence-based summary aligned to the 2026 MLA Content Map. It is intended for medical students and junior doctors preparing for the UKMLA. Always cross-reference with NICE guidance, local protocols, and clinical judgement.
The Bottom Line
- Bipolar I: ≥1 manic episode (± depression). Bipolar II: ≥1 hypomanic + ≥1 depressive episode (NO full mania)
- Mania: elevated/irritable mood, grandiosity, reduced sleep, pressured speech, disinhibition, psychotic features — ≥7 days or requiring hospitalisation
- Hypomania: milder form of mania — elevated mood, increased energy, reduced sleep need — 4+ days, no psychosis, not requiring admission
- Acute mania: stop antidepressant + start antipsychotic (haloperidol, olanzapine, risperidone, or quetiapine) ± short-term benzodiazepine
- Long-term prophylaxis: lithium is first-line (NICE CG185). Alternatives: valproate, olanzapine, quetiapine, lamotrigine (mainly for depressive episodes)
- Lithium: narrow therapeutic index (0.6–0.8 mmol/L for prophylaxis). Requires monitoring: levels, renal function, thyroid, calcium every 6 months
Overview
Bipolar affective disorder is a chronic, episodic mood disorder characterised by recurrent episodes of abnormally elevated mood (mania or hypomania) and depression. Bipolar I requires at least one manic episode (with or without depressive episodes). Bipolar II requires at least one hypomanic and one major depressive episode, without a history of full mania. Mania involves elevated or irritable mood, grandiosity, reduced need for sleep, pressured speech, flight of ideas, distractibility, increased goal-directed activity, and risky behaviour lasting ≥7 days (or any duration if hospitalisation is required). Psychotic features (grandiose or persecutory delusions, hallucinations) may occur in mania. Hypomania is a milder form lasting ≥4 days without psychosis or functional impairment requiring admission.
Epidemiology
Bipolar disorder has a lifetime prevalence of approximately 1–2%. It affects men and women equally. Mean age of onset is 20–25 years, though diagnosis is often delayed by 5–10 years. There is a strong genetic component — first-degree relatives have a 5–10× increased risk. The heritability is estimated at 80–85%. Bipolar disorder is frequently misdiagnosed as unipolar depression because patients typically present during depressive episodes rather than manic/hypomanic episodes. Comorbidity with substance misuse (~40–60%), anxiety disorders, and ADHD is common.
Clinical Features
Symptoms
Mania: elevated, expansive, or irritable mood — sustained change lasting ≥7 days
Grandiosity: inflated self-esteem, believing one has special powers/abilities/connections
Reduced need for sleep: sleeping 2–3 hours yet feeling rested and energised
Pressured speech: talking rapidly, difficult to interrupt, loud
Flight of ideas: rapidly shifting between loosely connected topics
Increased goal-directed activity: starting multiple projects, excessive planning, overworking
Disinhibition and risky behaviour: excessive spending, sexual indiscretions, reckless driving, poor judgement
Psychotic features (in mania): grandiose delusions, auditory hallucinations, persecutory ideas
Depressive episodes: as per major depression — low mood, anhedonia, fatigue, hopelessness, suicidal ideation
Signs
Psychomotor agitation, restlessness, distractibility
Bright, colourful, inappropriate clothing or appearance
Pressure of speech, tangential thought, flight of ideas on MSE
Elevated or labile mood — may rapidly switch to irritability
Poor insight — patient may deny they are unwell (especially in mania)
Investigations
First-line
Clinical assessment (MSE)Detailed psychiatric history and mental state examination. Establish mood episode type, duration, severity, psychotic features, insight, risk
Mood Disorder Questionnaire (MDQ)Screening tool for bipolar features in patients presenting with depression — 13 items
Collateral historyEssential — patients in mania lack insight. Information from family/friends about behaviour change, sleep pattern, spending
Second-line
BloodsTFTs (lithium-related or hyperthyroidism differential), FBC, U&Es, LFTs, calcium, glucose, lipids, HbA1c (metabolic monitoring for antipsychotics)
Urine drug screenExclude substance-induced mania (cocaine, amphetamines, cannabis)
Specialist
Baseline investigations before lithiumU&Es, eGFR, TFTs, calcium, ECG, pregnancy test. Weight, BMI at baseline
1
Acute mania or hypomania
- STOP any antidepressant (can precipitate mania or rapid cycling)
- If not already on a mood stabiliser: start antipsychotic — haloperidol, olanzapine, risperidone, or quetiapine
- If already on lithium: check level and optimise (target 0.8–1.0 mmol/L in acute mania)
- Short-term benzodiazepine (lorazepam) for agitation, insomnia, or behavioural disturbance
- Consider hospital admission (voluntary or under Mental Health Act if lacking capacity/insight)
2
Acute bipolar depression
- Fluoxetine + olanzapine combination, or quetiapine monotherapy, or lamotrigine
- If antidepressant used: ALWAYS combine with antimanic agent (mood stabiliser or antipsychotic) — never give SSRI alone
- Psychological therapy: structured psychological intervention (CBT adapted for bipolar)
3
Long-term prophylaxis (NICE first-line: lithium)
- Lithium: target serum level 0.6–0.8 mmol/L for prophylaxis (0.8–1.0 mmol/L in acute mania)
- Lithium monitoring: levels every 3 months (then 6-monthly when stable), U&Es, TFTs, calcium every 6 months
- Warn about: toxicity symptoms (tremor, diarrhoea, vomiting, confusion), drug interactions (NSAIDs, ACE inhibitors, diuretics), dehydration risk
- Alternatives if lithium not suitable: valproate (NOT in women of childbearing age — teratogenic), olanzapine, quetiapine
- Lamotrigine: effective for preventing depressive episodes (less effective for mania)
4
Valproate safety
- Valproate is CONTRAINDICATED in women/girls of childbearing potential unless Pregnancy Prevention Programme in place
- Teratogenic: neural tube defects, neurodevelopmental delay in up to 30–40% of exposed pregnancies
- MHRA Valproate Pregnancy Prevention Programme: annual specialist review, signed Risk Acknowledgement Form
Complications
- Suicide: ~15–20× increased risk. 25–50% attempt suicide during lifetime. Highest risk during depressive and mixed episodes
- Substance misuse: 40–60% comorbidity — worsens course and prognosis
- Lithium toxicity: >1.5 mmol/L — tremor, diarrhoea, vomiting, ataxia, renal failure, seizures. Medical emergency at >2.0 mmol/L
- Metabolic syndrome: Weight gain, diabetes, dyslipidaemia from antipsychotics (especially olanzapine)
- Relationship and occupational breakdown: Impulsive behaviour during mania, withdrawal during depression
- Rapid cycling: ≥4 mood episodes per year — more treatment-resistant
UKMLA Exam Tips
- 1Bipolar I = at least one MANIC episode (± depression). Bipolar II = HYPOMANIA + DEPRESSION (no full mania)
- 2Mania ≥7 days (or any duration if hospitalised). Hypomania ≥4 days, no psychosis, no admission needed
- 3NEVER give an SSRI alone in bipolar depression — risk of switching to mania. Always combine with mood stabiliser
- 4Lithium therapeutic range: 0.6–0.8 mmol/L (prophylaxis), 0.8–1.0 mmol/L (acute mania). Toxicity >1.5 mmol/L
- 5Lithium toxicity precipitants: dehydration, NSAIDs, ACE inhibitors, thiazides — exam favourite
- 6Valproate: NEVER in women of childbearing potential without Pregnancy Prevention Programme. Highly teratogenic
- 7Young patient with depression + family history of bipolar → always screen for previous hypomania before starting SSRI
practicetest your knowledge on bipolar affective disorderApply what you've learnt with UKMLA-style questions from the iatroX Q-Bank — psychiatry and beyond.
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