Master Mental Health
for AMC Cat 1

What the AMC Cat 1 Tests in Mental Health

This exam tests the ability to diagnose and manage common psychiatric disorders in primary care and emergency settings. Candidates must differentiate organic from functional illness, apply DSM-5/ICD-11 criteria for major depression, bipolar disorder, schizophrenia, and anxiety disorders. Key decisions include initiating antidepressants (SSRIs), antipsychotics (olanzapine, risperidone), and mood stabilisers (lithium, valproate); recognising serotonin syndrome, neuroleptic malignant syndrome, and lithium toxicity. Suicide risk assessment using the SAD PERSONS scale, capacity assessment under the Mental Capacity Act, and indications for involuntary admission under mental health legislation are essential. Substance use disorders, especially alcohol withdrawal management (CIWA-Ar protocol, benzodiazepine dosing), and opioid substitution therapy (methadone, buprenorphine) are frequently tested.

High-Yield Concepts

• Major Depressive Disorder – Diagnosis and First-Line Treatment: DSM-5 requires ≥5 symptoms (including depressed mood or anhedonia) for ≥2 weeks. First-line pharmacotherapy: SSRIs (sertraline 50 mg, escitalopram 10 mg) or SNRIs (venlafaxine). Assess for suicidality before starting; warn about initial activation and delayed onset (2-4 weeks). Augment with aripiprazole or switch if no response after 6-8 weeks.
• Bipolar Disorder – Acute Mania and Maintenance: ICD-11: elevated mood, increased energy, grandiosity, reduced need for sleep. First-line acute: lithium (target 0.6-1.2 mmol/L) or valproate (500-1000 mg) plus a short-term antipsychotic (olanzapine 10-20 mg). Avoid antidepressants. Maintenance: lithium reduces suicide risk. Monitor renal/thyroid function and lithium levels every 3-6 months.
• Schizophrenia – Positive Symptoms and Antipsychotic Choice: First-episode psychosis: start oral olanzapine 5-10 mg or risperidone 2-4 mg. Monitor for extrapyramidal side effects (EPS) and metabolic syndrome (weight, lipids, glucose). Clozapine is reserved for treatment-resistant schizophrenia (≥2 failed trials). Use PANSS or BPRS to track response. Ensure baseline ECG for QT interval.
• Alcohol Withdrawal – CIWA-Ar Protocol and Benzodiazepine Dosing: CIWA-Ar score ≥10 indicates need for medication. First-line: diazepam 10-20 mg or chlordiazepoxide 50-100 mg hourly as needed. For severe withdrawal (CIWA >20), consider IV lorazepam. Give parenteral thiamine (Pabrinex) before glucose to prevent Wernicke's encephalopathy. Monitor for seizures and delirium tremens.
• Suicide Risk Assessment – SAD PERSONS Scale and Immediate Management: SAD PERSONS: Sex (male), Age (<25 or >60), Depression, Previous attempt, Ethanol abuse, Rational thinking loss, Social support lacking, Organised plan, No spouse, Sickness. Score ≥6 indicates high risk: admit to psychiatric unit, remove means, start safety plan. Always document risk level and follow-up.
• Serotonin Syndrome – Recognition and Management: Triad: altered mental status, autonomic instability (tachycardia, hypertension, hyperthermia), neuromuscular abnormalities (clonus, hyperreflexia). Most common with MAOI + SSRI/SNRI or overdose. Stop all serotonergic drugs; treat with cyproheptadine (12 mg PO then 2 mg q2h) if moderate-severe. Supportive care including cooling and benzodiazepines for agitation.
• Neuroleptic Malignant Syndrome – Diagnosis and Immediate Steps: Hyperthermia (>38°C), rigidity, altered consciousness, autonomic dysfunction, elevated CK. Stop antipsychotic immediately. Start dantrolene (1-2.5 mg/kg IV) or bromocriptine (2.5-5 mg PO TID). Supportive: IV fluids, cooling, monitor renal function. Rechallenge with atypical antipsychotic after 2 weeks.
• Capacity Assessment and Mental Health Act – Key Principles: Mental Capacity Act (UK/Australia): four-stage test – can person understand, retain, weigh, and communicate decision? If lacking capacity, treat in best interests. For involuntary admission under Mental Health Act: patient has mental disorder, risk of harm to self/others, and need for treatment. Use sections 2 (assessment) or 3 (treatment) in England; in Australia, state-specific legislation (e.g., NSW Mental Health Act 2007).

Common Traps in Mental Health Questions

• Confusing bipolar depression with unipolar depression: never start an antidepressant without a mood stabiliser in bipolar disorder, as it can trigger mania.
• Using low-potency antipsychotics (chlorpromazine) in elderly patients with dementia: increases stroke risk and mortality; use risperidone or haloperidol cautiously.
• Forgetting to check lithium levels before starting therapy and not adjusting for renal impairment; target range is 0.6-1.2 mmol/L, not a fixed dose.
• Missing serotonin syndrome when a patient on SSRIs presents with hyperthermia and clonus, especially if they recently added a triptan or St John's wort.
• Assuming a patient with alcohol dependence can be safely withdrawn at home without CIWA-Ar monitoring or thiamine prophylaxis, leading to Wernicke's encephalopathy.
• Neglecting to document capacity assessment and the specific criteria for involuntary admission, which is a common medicolegal pitfall.

How to Revise Mental Health for the AMC Cat 1

Prioritise high-stakes, time-critical presentations: acute psychosis, suicidal ideation, alcohol withdrawal, and serotonin/NMS emergencies. Questions are often scenario-based, requiring you to choose the next best step (e.g., which medication, which scale, whether to admit). Practise applying DSM-5/ICD-11 criteria to vignettes and calculating CIWA-Ar scores. Memorise key drug doses, monitoring parameters (lithium, clozapine), and side-effect profiles. For medicolegal questions, know the MCA vs MHA distinction and when to use each. Review the SAD PERSONS and CIWA-Ar tools in detail. Spend time on substance misuse management, as it is a recurring theme. Use past AMC questions to familiarise yourself with the style of 'choose the most appropriate management' rather than esoteric theory.

Practise it: MedLumen has 100 Mental Health questions for the AMC Cat 1, each with a full explanation and references.