Master Psychiatry
for PLAB 1

What the PLAB 1 Tests in Psychiatry

Psychiatry in PLAB 1 tests the ability to recognise common psychiatric disorders in primary care and emergency settings, select appropriate pharmacological and psychological first-line treatments, and apply the Mental Health Act (England & Wales) for detention. Candidates must differentiate between depression, bipolar disorder, schizophrenia, anxiety disorders, OCD, PTSD, eating disorders, and substance misuse. Key decisions include choosing SSRIs (e.g., sertraline, fluoxetine) for depression and anxiety, lithium or valproate for bipolar prophylaxis, and antipsychotics (e.g., olanzapine, risperidone) for psychosis. The exam also assesses knowledge of side-effect profiles (e.g., extrapyramidal symptoms, weight gain, QTc prolongation), basic psychological therapies (CBT, DBT), and risk assessment for suicide and self-harm. Specific diagnostic criteria (ICD-10/DSM-5) are tested, along with management of delirium, dementia, and alcohol withdrawal (CIWA-Ar protocol).

High-Yield Concepts

• Depression – Diagnosis and First-Line Treatment: ICD-10 requires at least 2 core symptoms (low mood, anhedonia, fatigue) plus other symptoms for 2 weeks. First-line: SSRI (sertraline 50 mg or fluoxetine 20 mg daily). For severe depression with psychotic features, add olanzapine or risperidone. Do not prescribe St John's Wort in the UK due to interactions.
• Bipolar Disorder – Acute Mania and Prophylaxis: Acute mania: first-line is olanzapine or haloperidol. For mixed episodes or rapid cycling, valproate semisodium is preferred. Lithium remains first-line for prophylaxis (target serum level 0.6–1.0 mmol/L). Monitor renal and thyroid function every 6 months.
• Schizophrenia – Positive and Negative Symptoms: First-line antipsychotic: oral olanzapine 10 mg/day or risperidone 4–6 mg/day. For treatment-resistant schizophrenia, clozapine is indicated (requires FBC monitoring for agranulocytosis). Negative symptoms (apathy, social withdrawal) respond poorly to antipsychotics; consider CBT.
• Generalised Anxiety Disorder (GAD) – Treatment: First-line: SSRI (sertraline 50 mg) or SNRI (duloxetine 60 mg). CBT is equally effective. Avoid benzodiazepines beyond 2–4 weeks due to dependence risk. For acute severe anxiety, consider pregabalin 150–300 mg/day (licensed for GAD in the UK).
• Obsessive-Compulsive Disorder (OCD) – Management: First-line: high-dose SSRI (fluoxetine up to 60 mg, sertraline up to 200 mg) or clomipramine (a tricyclic). CBT with exposure and response prevention (ERP) is the psychological treatment of choice. Treatment response may take 8–12 weeks.
• Alcohol Withdrawal – CIWA-Ar Protocol: Use the Clinical Institute Withdrawal Assessment for Alcohol (CIWA-Ar) scale. Score <10: no medication; 10–20: chlordiazepoxide 20–40 mg PRN; >20: chlordiazepoxide 40–80 mg. Severe withdrawal with seizures: IV lorazepam. Always give thiamine (Pabrinex) IV to prevent Wernicke's encephalopathy.
• Delirium vs Dementia – Key Distinguishing Features: Delirium: acute onset, fluctuating consciousness, hallucinations (visual), disorientation, and inattention. Dementia: gradual onset, stable consciousness, memory loss, but normal attention until late stages. Delirium is a medical emergency – treat underlying cause (e.g., infection, electrolyte imbalance).
• Mental Health Act (MHA) 1983 – Sections Relevant to PLAB: Section 2: 28-day assessment order (2 doctors + AMHP). Section 3: 6-month treatment order (2 doctors + AMHP). Section 4: 72-hour emergency order (1 doctor). Section 5(2): 72-hour holding power for inpatients (doctor's order). Section 136: police power to remove a person from a public place to a place of safety for 24 hours.

Common Traps in Psychiatry Questions

• Confusing Section 2 (assessment) with Section 3 (treatment) – remember Section 2 is for assessment, Section 3 for treatment.
• Using benzodiazepines as first-line for anxiety disorders instead of SSRIs – benzodiazepines are only for short-term crisis.
• Giving olanzapine IM for acute agitation without checking QTc – olanzapine prolongs QTc, especially with other drugs.
• Forgetting to monitor lithium levels (every 3–6 months) and renal/thyroid function – lithium toxicity is a common exam pitfall.
• Assuming all antipsychotics are equal for negative symptoms – first-generation (haloperidol) worsen negative symptoms; second-generation (olanzapine, risperidone) are preferred.
• Missing delirium in elderly patients with dementia – always suspect delirium if acute confusion, not just dementia progression.

How to Revise Psychiatry for the PLAB 1

Focus on first-line pharmacological choices (SSRIs, antipsychotics, mood stabilisers) and their side-effect profiles. Questions often present a clinical scenario (e.g., a 45-year-old woman with low mood, insomnia, and weight loss) and ask for the most appropriate initial drug or referral. Practice distinguishing between depression and bipolar depression (never give antidepressant monotherapy in bipolar). Know the MHA sections by number and purpose, especially Sections 2, 3, and 5(2). Delirium vs dementia is a recurring theme – memorise the onset and consciousness differences. For substance misuse, master the CIWA-Ar protocol and Wernicke's prophylaxis. Use NICE guidelines as your standard. Revise using single-best-answer questions from past PLAB 1 banks to get used to the format.

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