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Mood Disorders: Depression & Bipolar – MRCP Part 1

TL;DR

Mood disorders are a high-yield psychiatry topic in MRCP Part 1, most commonly testing diagnostic criteria, differentiation between unipolar depression and bipolar disorder, and first-line pharmacology. Examiners favour subtle distinctions such as mania versus hypomania, antidepressant-induced switching, and lithium safety. This article provides an exam-focused framework, a worked MCQ, common traps, and a practical revision checklist.


Why mood disorders matter in MRCP Part 1

Psychiatry contributes a reliable proportion of questions in MRCP Part 1, and mood disorders form one of its most predictable areas. Questions are rarely vague: they test whether candidates can apply definitions, durations, exclusions, and drug safety rather than broad descriptions.

Most stems are clinically realistic and short. A single missed clue—such as a past hypomanic episode or renal impairment in a patient on lithium—often determines the correct answer. For syllabus context, review the official structure on the MRCP(UK) website and the Crack Medicine hub:


Scope of examinable content

For MRCP Part 1, mood disorders are assessed through:

  • Core diagnostic criteria (ICD-10 / DSM-5 principles)

  • Differentiation of depressive episodes, mania, and hypomania

  • Bipolar subtypes and course patterns

  • Antidepressants and mood stabilisers (indications, risks, adverse effects)

  • Organic and drug-induced mood disorders

  • Suicide risk and emergency management principles

Psychotherapy models and detailed rating scales are not examined.


High-yield outline: what to know cold

1. Major depressive disorder (unipolar depression)

  • At least 2 weeks of persistent low mood and/or anhedonia

  • Associated symptoms: sleep disturbance, appetite change, fatigue, poor concentration, guilt, suicidal ideation

  • Always exclude past mania or hypomania before diagnosing unipolar depression

2. Bipolar affective disorder

  • Bipolar I: at least one manic episode (depression may or may not occur)

  • Bipolar II: hypomanic episodes plus major depressive episodes, no full mania

3. Mania vs hypomania (classic exam discriminator)

  • Mania:

    • ≥7 days (or any duration if hospitalisation required)

    • Marked functional impairment

    • Psychotic features may occur

  • Hypomania:

    • ≥4 days

    • No psychosis

    • No severe social or occupational dysfunction

4. Antidepressants

  • SSRIs are first-line for moderate–severe unipolar depression

  • Can precipitate mania or rapid cycling in bipolar disorder

  • Common adverse effects: GI upset, sexual dysfunction, QT prolongation (specific agents), hyponatraemia (elderly)

5. Mood stabilisers

  • Lithium:

    • Gold standard for relapse prevention

    • Narrow therapeutic index

    • Adverse effects: tremor, hypothyroidism, nephrogenic diabetes insipidus

  • Valproate: effective but teratogenic

  • Lamotrigine: bipolar depression and maintenance (risk of Stevens–Johnson syndrome)

6. Rapid cycling bipolar disorder

  • ≥4 mood episodes in 12 months

  • Associated with poorer prognosis

  • Antidepressants may worsen cycling

7. Psychotic depression

  • Mood-congruent delusions or hallucinations

  • Requires antidepressant plus antipsychotic or ECT

8. Organic and secondary causes

  • Hypothyroidism, Parkinson’s disease, stroke, corticosteroids

  • Late-onset depression is organic until proven otherwise


Most tested subtopics at a glance

Subtopic

What MRCP Part 1 tests

Diagnostic thresholds

Duration, severity, exclusion of mania

Mania vs hypomania

Functional impairment, psychosis

Lithium

Side effects, interactions, monitoring

Antidepressants

Switching to mania, serotonin syndrome

Special groups

Pregnancy, renal disease, elderly

MRCP Part 1 psychiatry study setup with notes on mood disorders

Mini-case (MCQ style)

Question A 29-year-old woman presents with 5 days of elevated mood, reduced need for sleep, increased talkativeness, and increased goal-directed activity. She continues to attend work and reports feeling unusually productive. There is no psychosis. She has had two previous depressive episodes.

What is the most likely diagnosis?

A. ManiaB. HypomaniaC. CyclothymiaD. Schizoaffective disorderE. Major depressive disorder

Correct answer: B. Hypomania

Explanation The episode lasts ≥4 days, lacks psychotic features, and does not cause marked functional impairment. A history of depressive episodes plus hypomania supports bipolar II disorder. Mania would require severe impairment, hospitalisation, or psychosis.


Five common exam traps

  • Diagnosing unipolar depression without excluding past hypomania

  • Misclassifying hypomania as mania due to symptom intensity alone

  • Forgetting lithium contraindications (renal disease, dehydration, ACE inhibitors)

  • Ignoring medical causes of new-onset depression in older adults

  • Assuming antidepressants are always safe in bipolar disorder


Practical study-tip checklist

  • Memorise time thresholds (2 weeks, 4 days, 7 days)

  • Create a one-page mania vs hypomania comparison

  • Pair each drug with one major adverse effect

  • Practise psychiatry questions regularly using a real question bank:https://www.crackmedicine.com/qbank/

  • Use short, spaced reviews rather than long psychiatry-only sessions

For structured teaching, see psychiatry-focused sessions here:https://www.crackmedicine.com/lectures/


FAQs

Is bipolar disorder commonly tested in MRCP Part 1?

Yes. Bipolar disorder is frequently examined, particularly the distinction between mania and hypomania and medication-related risks.

How much pharmacology do I need to know?

Focus on indications, major adverse effects, and contraindications rather than detailed dosing.

Can SSRIs cause mania in exam questions?

Yes. Antidepressant-induced switching is a classic MRCP Part 1 theme.

Is ECT within the MRCP Part 1 syllabus?

Yes. Indications and common adverse effects are examinable, not procedural details.


Ready to start?

Consolidate this topic by attempting psychiatry blocks from the Practise psychiatry MCQs section and revisiting the MRCP Part 1 overview hub to track syllabus coverage.


Sources

 
 
 

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