Master Psychiatry
for MRCP Part 1

What the MRCP Part 1 Tests in Psychiatry

The MRCP Part 1 Psychiatry section tests the ability to recognise and manage common psychiatric presentations in medical and surgical settings, focusing on delirium, dementia, depression, anxiety, psychosis, and substance misuse. Candidates must demonstrate knowledge of diagnostic criteria (ICD-10/DSM-5), first-line pharmacological and non-pharmacological treatments, key side effects of psychotropic drugs, and medico-legal frameworks (Mental Health Act, capacity assessment). Questions often present clinical vignettes with physical comorbidity, requiring differentiation between organic and functional disorders. Emphasis is on safe prescribing in medically ill patients, drug interactions (e.g., SSRIs with warfarin, lithium with NSAIDs), and emergency management of agitation, overdose, and catatonia. Practical aspects such as screening tools (e.g., PHQ-9, GAD-7, MMSE), delirium risk factors, and withdrawal syndromes are high yield.

High-Yield Concepts

• Delirium vs Dementia: Delirium is acute onset (hours to days), fluctuating consciousness, inattention, and disorganised thinking; key causes: infection, electrolyte disturbance, drugs (anticholinergics). First-line management: identify and reverse cause, haloperidol 0.5–1 mg IM/PO for agitation (avoid in Parkinson's/Lewy body dementia). Dementia: gradual onset, clear consciousness, MMSE <24 suggests cognitive impairment; treat Alzheimer's with donepezil (5–10 mg OD) or rivastigmine.
• Depression: Diagnosis and First-Line Treatment: ICD-10 requires at least 2 core symptoms (low mood, anhedonia, reduced energy) plus 2-3 other symptoms for mild/moderate episode, 4+ for severe. First-line: SSRI (sertraline 50 mg OD or citalopram 20 mg OD); monitor for hyponatraemia (especially elderly) and GI bleeding (avoid NSAIDs). For severe depression with psychotic features: add olanzapine 5–10 mg OD or aripiprazole.
• Lithium Monitoring and Toxicity: Therapeutic range: 0.4–1.0 mmol/L (maintenance), 0.8–1.2 mmol/L for acute mania. Check renal function, TFTs, and calcium before starting; monitor levels every 3-6 months. Toxicity (levels >1.5): tremor, ataxia, slurred speech, seizures; urgent management: IV fluids, haemodialysis if severe. Avoid NSAIDs, ACE inhibitors, thiazide diuretics which raise lithium levels.
• Antipsychotic Side Effects: Typical (haloperidol): extrapyramidal symptoms (acute dystonia, parkinsonism, akathisia) – treat with procyclidine 5–10 mg IM/IV. Atypical (olanzapine, clozapine): metabolic syndrome (weight gain, diabetes, dyslipidaemia), QT prolongation (monitor ECG for QTc >500 ms). Clozapine requires mandatory FBC monitoring for agranulocytosis (WCC <3.0 ×10⁹/L).
• Alcohol Withdrawal and Wernicke-Korsakoff: CIWA-Ar score guides benzodiazepine dosing (e.g., chlordiazepoxide 10–20 mg QDS). For Wernicke encephalopathy (confusion, ataxia, nystagmus): give IV Pabrinex (thiamine 250 mg) immediately before glucose. Korsakoff syndrome: irreversible anterograde amnesia. Prevent with oral thiamine 200–300 mg daily in at-risk drinkers.
• Mental Health Act (England & Wales) – Key Sections: Section 2: 28-day assessment order (2 doctors + AMHP). Section 3: 6-month treatment order (renewable). Section 4: 72-hour emergency order (1 doctor). Section 5(2): 72-hour holding power for inpatients (by treating doctor). Capacity assessment (MCA 2005): must assess ability to understand, retain, weigh and communicate decision; applies to physical health decisions even under MHA.
• Serotonin Syndrome vs Neuroleptic Malignant Syndrome: Serotonin syndrome: hyperthermia, clonus, hyperreflexia, myoclonus, agitation – caused by SSRI/MAOI combination; treat with cyproheptadine 12 mg PO. NMS: rigidity, bradyreflexia, autonomic instability, elevated CK – caused by antipsychotics; treat with dantrolene 1–2.5 mg/kg IV or bromocriptine. Differentiate by history and presence of clonus.
• ECT Indications and Contraindications: Indications: severe depression (especially with psychotic features or catatonia), treatment-resistant depression, acute mania, catatonia. Relative contraindications: raised ICP, recent MI (within 3 months), unstable aneurysm. Pre-ECT workup: FBC, U&E, ECG, anaesthetic review. Common side effect: transient anterograde amnesia.

Common Traps in Psychiatry Questions

• Confusing delirium with dementia: delirium has acute onset and fluctuating consciousness, while dementia is chronic with clear consciousness.
• Prescribing haloperidol for agitation in Lewy body dementia or Parkinson's disease – can cause severe rigidity and neuroleptic sensitivity.
• Giving glucose to an alcoholic patient without thiamine first – precipitates Wernicke encephalopathy.
• Assuming capacity is all-or-nothing: capacity is decision-specific and must be assessed for each medical decision separately.
• Using benzodiazepines alone for severe alcohol withdrawal without checking for thiamine deficiency – risk of Korsakoff syndrome.
• Forgetting to check QTc interval before starting antipsychotics, especially in elderly or those on other QT-prolonging drugs (e.g., amiodarone, citalopram).

How to Revise Psychiatry for the MRCP Part 1

Prioritise high-yield topics: delirium (especially in elderly surgical patients), depression with medical comorbidity (e.g., post-MI, stroke), and alcohol withdrawal management. Questions are often integrated with general medicine – expect vignettes where a psychiatric condition mimics or complicates a physical illness (e.g., hyponatraemia from SSRIs, serotonin syndrome post-op). Practise interpreting ABG and ECG alongside psychiatric presentations (e.g., salicylate overdose causing agitation). Know ICD-10 criteria for major depression and generalised anxiety disorder, and the key differences between typical and atypical antipsychotics. Review NICE guidelines for depression (CG90) and psychosis (CG178). Spend time on drug interactions (lithium-NSAIDs, MAOI-tyramine) and side effect profiles. Use question banks that emphasise management decisions rather than pure recall – e.g., 'what is the next step in management?' rather than 'what is the diagnosis?'.

Practise it: MedLumen has 50 Psychiatry questions for the MRCP Part 1, each with a full explanation and references.