Bipolar affective disorder

Overview

Bipolar I vs Bipolar II
FeatureBipolar IBipolar II
Elevated mood episodeFull maniaHypomania only
PsychosisCan occur (grandiose/persecutory delusions, hallucinations)Not present
HospitalisationOften requiredNot required
Functional impairmentSevereMild-moderate

Feature	Bipolar I	Bipolar II
Elevated mood episode	Full mania	Hypomania only
Psychosis	Can occur (grandiose/persecutory delusions, hallucinations)	Not present
Hospitalisation	Often required	Not required
Functional impairment	Severe	Mild-moderate

Presentation

•Elevated/expansive mood - euphoria or uncharacteristic irritability

•Grandiosity - inflated self-esteem, extravagant plans, spending sprees

•Decreased need for sleep - feels rested after 2-3 hours (differs from insomnia)

•Pressured speech - rapid, loud, difficult to interrupt

•Flight of ideas - rapid topic changes WITH discernible links; listener can follow the thread

•Distractibility - attention easily drawn to irrelevant stimuli

•Increased goal-directed activity - multiple simultaneous projects

•Risky behaviour - gambling, sexual disinhibition, reckless driving

•Psychotic features (Bipolar I only) - grandiose delusions, persecutory delusions, auditory hallucinations

🎯
Flight of ideas vs knight's move thinking - Flight of ideas (mania): rapid topic changes WITH discernible links. Knight's move/loosening of associations (schizophrenia): topic changes with NO discernible links. This distinction is high-yield.

•Depressive episodes - present more frequently than manic episodes; mirrors MDD (depressed mood, anhedonia, suicidal ideation); mania/hypomania may only be elicited on careful history

Investigations

•Bipolar disorder is a clinical diagnosis - made by a specialist; no confirmatory biomarker

•First-line bloods: FBC, U&E (renal baseline before lithium), TFTs (thyroid disease mimics mania/depression), fasting glucose, lipids, urine drug screen

•ECG - baseline before lithium or antipsychotic; assess QTc

🏆 Gold standard

•specialist psychiatric assessment (secondary care)

Differential diagnosis

Key differentials
ConditionDistinguishing features
Borderline personality disorderRapid mood fluctuation WITHOUT discrete manic/hypomanic episodes; impulsive self-harm; fear of abandonment; history of childhood abuse; unstable relationships
SchizophreniaPsychosis in ABSENCE of prominent mood episodes; negative symptoms precede positive; no discrete mood episodes
Schizoaffective disorderPsychotic symptoms persist OUTSIDE of mood episodes (vs Bipolar I where psychosis is tied to the episode)
Unipolar MDDNo lifetime manic or hypomanic episode - always explore past history of elevated mood

Condition	Distinguishing features
Borderline personality disorder	Rapid mood fluctuation WITHOUT discrete manic/hypomanic episodes; impulsive self-harm; fear of abandonment; history of childhood abuse; unstable relationships
Schizophrenia	Psychosis in ABSENCE of prominent mood episodes; negative symptoms precede positive; no discrete mood episodes
Schizoaffective disorder	Psychotic symptoms persist OUTSIDE of mood episodes (vs Bipolar I where psychosis is tied to the episode)
Unipolar MDD	No lifetime manic or hypomanic episode - always explore past history of elevated mood

⚠️
Antidepressants used without a mood stabiliser can unmask or precipitate a manic episode in undiagnosed bipolar disorder - a common exam scenario.

Management

•Acute mania - first-line: haloperidol, olanzapine, or risperidone for rapid symptom control

•Acute mania - adjunct: lorazepam for short-term agitation if antipsychotic alone insufficient

•Acute mania - third-line: ECT for severe, treatment-resistant mania

•Bipolar depression - first-line: quetiapine monotherapy

•Bipolar depression - second-line: lithium or lamotrigine augmentation

•Long-term mood stabilisation - first-line: lithium - most evidence-based; also reduces suicide risk

•Long-term - second-line: valproate, olanzapine, quetiapine, or lamotrigine (lamotrigine particularly for Bipolar II with predominant depression)

🚨
Do NOT use antidepressants alone in bipolar depression - risks precipitating a manic switch or inducing rapid cycling. If used, must be combined with a mood stabiliser under specialist guidance.

⚠️
Sodium valproate is CONTRAINDICATED in women of childbearing potential unless enrolled in the Pregnancy Prevention Programme - causes neural tube defects and neurodevelopmental harm.

•Lithium monitoring: serum levels every 3-6 months when stable (therapeutic range 0.4-1.0 mmol/L); renal function and TFTs every 6 months

•Lithium toxicity (>1.5 mmol/L) - coarse tremor, vomiting, ataxia, confusion; severe: seizures, arrhythmias. Risk increased by dehydration, NSAIDs, ACE inhibitors, thiazide diuretics

•Admission: consider during manic episode (insight typically lost); MHA Section 2 (assessment up to 28 days) or Section 3 (treatment up to 6 months) if patient refuses voluntary admission