Professional and Linguistic Assessments Board (PLAB) Psychiatry and Mental Health Syllabus

In paracetamol overdose, when is the plasma paracetamol level most reliably interpreted on the treatment nomogram, and what is the antidote?

The level is plotted on the nomogram from 4 hours post-ingestion onwards (levels before 4 h are unreliable). The antidote is N-acetylcysteine (NAC). Treat staggered/uncertain-time overdoses with NAC regardless of level.

What are the Schneiderian first-rank symptoms of schizophrenia?

Auditory hallucinations (thought echo, running commentary, third-person voices), thought interference (insertion, withdrawal, broadcasting), passivity phenomena/delusions of control, and delusional perception.

How do positive and negative symptoms of schizophrenia differ? Give examples of each.

Positive symptoms (added experiences): hallucinations, delusions, thought disorder, disorganised behaviour. Negative symptoms (lost functions): blunted affect, alogia (poverty of speech), avolition, anhedonia, and social withdrawal.

What is the ICD-10 minimum symptom duration for a diagnosis of schizophrenia, and what is the first-line drug class?

Symptoms (e.g. ≥1 first-rank symptom or ≥2 other characteristic symptoms) must be present for most of the time for at least 1 month. First-line treatment is an atypical (second-generation) antipsychotic.

Which antipsychotic is reserved for treatment-resistant schizophrenia, what defines treatment resistance, and what serious haematological side effect requires monitoring?

Clozapine. Treatment resistance = inadequate response to ≥2 antipsychotics (one being atypical), each at adequate dose for ≥6–8 weeks. Clozapine can cause agranulocytosis/neutropenia, mandating regular FBC monitoring (weekly initially).

What is neuroleptic malignant syndrome (NMS) and its four cardinal features? What investigation is markedly raised?

A life-threatening reaction to antipsychotics. Cardinal features: hyperthermia (pyrexia), 'lead-pipe' muscular rigidity, autonomic instability, and altered consciousness. Creatine kinase (CK) is markedly raised; treat by stopping the drug, supportive care, and dantrolene/bromocriptine.

List the extrapyramidal side effects (EPSEs) of antipsychotics and their typical time course.

Acute dystonia (hours–days, e.g. oculogyric crisis), akathisia (hours–weeks, motor restlessness), parkinsonism (days–weeks, bradykinesia/tremor/rigidity), and tardive dyskinesia (months–years, often irreversible orofacial movements).

Name three significant metabolic/endocrine side effects of atypical antipsychotics, especially olanzapine and clozapine.

Weight gain, impaired glucose tolerance/type 2 diabetes, and dyslipidaemia (metabolic syndrome). Hyperprolactinaemia (notably with risperidone) causing galactorrhoea, amenorrhoea, and sexual dysfunction is also common.

In acute behavioural disturbance, what is the recommended order of management strategies before considering rapid tranquillisation?

De-escalation first (calm environment, verbal de-escalation, address needs), then offer oral medication, and only use rapid tranquillisation (parenteral) if these fail and there is risk to the patient or others.

What is the typical first-line drug regimen for rapid tranquillisation, and what reversal agents must be available?

IM lorazepam alone, or IM haloperidol plus IM promethazine. Have flumazenil available to reverse benzodiazepine-induced respiratory depression, and procyclidine for acute dystonia from haloperidol.

List the key clinical features distinguishing delirium from dementia.

Delirium: acute onset (hours–days), fluctuating course, impaired/clouded consciousness and attention, often reversible, with hallucinations/agitation. Dementia: insidious onset (months–years), progressive, clear consciousness until late, and chronic/irreversible.

What are the two motor subtypes of delirium, and which is more often missed?

Hyperactive delirium (agitation, restlessness, hallucinations) and hypoactive delirium (lethargy, withdrawal, drowsiness). Hypoactive delirium is more commonly missed because it is quieter and may be mistaken for depression.

Give a useful mnemonic for common precipitating causes of delirium.

'PINCH ME': Pain, Infection, Nutrition, Constipation, Hydration, Medication (and Metabolic), Environment. Drug causes and urinary retention are also frequent precipitants, especially in the elderly.

What is the most common cause of dementia, and what are its two characteristic neuropathological hallmarks?

Alzheimer's disease. Hallmarks are extracellular beta-amyloid (senile) plaques and intracellular neurofibrillary tangles of hyperphosphorylated tau protein, with cortical atrophy and acetylcholine deficiency.

Which drug classes are used in Alzheimer's disease, and how does treatment choice relate to severity?

Acetylcholinesterase inhibitors (donepezil, rivastigmine, galantamine) for mild-to-moderate disease; the NMDA-receptor antagonist memantine for moderate-to-severe disease or when AChE inhibitors are contraindicated/not tolerated.

What are the core clinical features that distinguish Lewy body dementia, and why must antipsychotics be used with caution?

Fluctuating cognition, recurrent well-formed visual hallucinations, and spontaneous parkinsonism; REM sleep behaviour disorder is supportive. Patients have severe neuroleptic sensitivity, so antipsychotics can cause profound, potentially fatal reactions and should be avoided/used cautiously.

What are the units thresholds for 'increasing risk' and 'higher risk' alcohol drinking, and the UK low-risk guideline?

UK low-risk guideline: ≤14 units/week spread over ≥3 days for both men and women. Increasing risk: 14–35 units/week (women) or 14–50 (men); higher risk: >35 (women) or >50 (men) units/week.

What screening tools are used for alcohol use disorders and dependence?

AUDIT (10-item, full screen) and AUDIT-C (3-item, brief) for hazardous/harmful drinking; CAGE (Cut down, Annoyed, Guilty, Eye-opener) is a quick 4-question screen for dependence.

What is the time course and danger of delirium tremens, and the first-line treatment?

Delirium tremens peaks 48–72 hours after the last drink, with confusion, tremor, hallucinations (often visual/tactile), autonomic instability and seizures; it carries significant mortality. First-line treatment is a reducing regimen of a long-acting benzodiazepine (chlordiazepoxide), plus parenteral thiamine (Pabrinex).

What is Wernicke's encephalopathy, its classic triad, and how is it prevented?

An acute thiamine (vitamin B1) deficiency. Classic triad: confusion, ataxia, and ophthalmoplegia/nystagmus. Prevented and treated with high-dose IV/IM thiamine (Pabrinex); untreated it may progress to irreversible Korsakoff's syndrome (anterograde amnesia, confabulation).

What pharmacological options support alcohol abstinence, and what is their mechanism?

Acamprosate (reduces craving via glutamate/GABA modulation), naltrexone (opioid antagonist reducing reward), and disulfiram (aversive—inhibits aldehyde dehydrogenase causing a flushing/vomiting reaction with alcohol).

What is the antidote for opioid overdose, its mechanism, and a key caution regarding its half-life?

Naloxone, a competitive opioid-receptor antagonist. Caution: its half-life is shorter than many opioids (e.g. methadone), so repeated doses or an infusion may be needed to prevent re-sedation.

Under the Mental Health Act 1983 (England & Wales), compare Section 2 and Section 3.

Section 2: admission for assessment, lasts up to 28 days, not renewable; requires 2 doctors + an AMHP. Section 3: admission for treatment, lasts up to 6 months (renewable), used where the diagnosis is known; also requires 2 doctors + an AMHP.

What do Sections 5(2) and 5(4) of the Mental Health Act allow, and for how long?

Section 5(2): a doctor can detain an already-admitted inpatient for up to 72 hours pending MHA assessment. Section 5(4): a nurse's holding power detains an inpatient for up to 6 hours. Neither permits treatment against the patient's will and they are not renewable.

Differentiate Section 135 and Section 136 of the Mental Health Act.

Section 135: police, with a magistrate's warrant, enter a private property to remove a person to a place of safety. Section 136: police remove a person who appears mentally disordered from a public place to a place of safety. Both last up to 24 hours (extendable by 12 h).

State the five statutory principles of the Mental Capacity Act 2005.

(1) Presume capacity. (2) Support the person to make their own decision. (3) An unwise decision does not mean lack of capacity. (4) Act in the person's best interests. (5) Choose the least restrictive option of their rights and freedoms.

What is the two-stage, four-part functional test of capacity under the Mental Capacity Act?

Stage 1: is there an impairment/disturbance of the mind or brain? Stage 2 (the functional test): can the person Understand the information, Retain it, Weigh/use it in the decision, and Communicate their decision? Failing any one of the four means they lack capacity for that decision.

In anorexia nervosa, what BMI threshold is characteristic, and name three physical/biochemical complications.

BMI typically <17.5 $\text{kg/m}^{2}$. Complications: bradycardia/hypotension, electrolyte disturbance (hypokalaemia), amenorrhoea, osteoporosis, lanugo hair, and the 'G's and C's raised'—Growth hormone, Glucose (cortisol), salivary Glands, Cholesterol, Carotenaemia raised; sex hormones/T3 low.

How is bulimia nervosa distinguished from anorexia, and what acid-base/electrolyte disturbance results from self-induced vomiting?

Bulimia features recurrent binge eating with compensatory behaviours (vomiting, laxatives), but body weight is usually normal/near-normal. Self-induced vomiting causes a hypokalaemic, hypochloraemic metabolic alkalosis.

What is refeeding syndrome, the key electrolyte abnormality, and how is it prevented?

A dangerous shift when feeding is reintroduced after starvation: insulin surge drives phosphate, potassium and magnesium into cells, causing hypophosphataemia (the hallmark), arrhythmias and cardiac failure. Prevent by slow calorie reintroduction, thiamine, and close electrolyte monitoring/replacement.

In perinatal psychiatry, compare 'baby blues', postnatal depression, and puerperal psychosis by onset and severity.

Baby blues: ~day 3–10, very common, mild/self-limiting, needs reassurance. Postnatal depression: typically within 1–3 months, depressive episode needing treatment (CBT/SSRI). Puerperal psychosis: rapid onset ~days 2 weeks postpartum, a psychiatric emergency with psychosis/mania needing urgent admission (often to a mother-and-baby unit).