PLAB 1 Psychiatry 2 — Questions and Answers
Question 1: A 45-year-old man presents after a suicide attempt by overdose. He has a clear plan, wrote a suicide note, and took steps to avoid being found. According to UK risk assessment guidelines, which features indicate the highest risk?
- The method used was an overdose rather than a violent method
- Evidence of planning, a suicide note, and precautions against discovery indicate high intent and high risk (Correct answer)
- The patient's age — younger patients are always higher risk
- The time of day the attempt was made
Correct answer: Evidence of planning, a suicide note, and precautions against discovery indicate high intent and high risk
High-risk features for completed suicide include: evidence of planning (not impulsive), writing a suicide note or final arrangements, precautions against discovery, use of a violent method, and ongoing suicidal intent. These features indicate high intent and require urgent psychiatric assessment and safety planning.
Question 2: A 60-year-old woman is started on lithium for bipolar disorder. What monitoring is essential before and during lithium treatment?
- No monitoring is required — lithium is a safe medication
- Baseline renal function, thyroid function, and ECG, with regular serum lithium levels maintained at 0.6-0.8 mmol/L (maintenance) (Correct answer)
- Only serum lithium levels need to be checked once at the start
- Annual liver function tests only
Correct answer: Baseline renal function, thyroid function, and ECG, with regular serum lithium levels maintained at 0.6-0.8 mmol/L (maintenance)
Lithium has a narrow therapeutic index. NICE requires baseline renal function (U&Es, eGFR), thyroid function (lithium can cause hypothyroidism), calcium, and ECG. Serum lithium levels should be checked 12 hours post-dose, weekly until stable, then every 3 months. Target range for maintenance is 0.6-0.8 mmol/L.
Question 3: A 30-year-old woman presents with episodes of binge eating followed by self-induced vomiting, occurring at least twice per week for the past 3 months. Her BMI is 22. What is the most likely diagnosis?
- Anorexia nervosa, binge-purge subtype
- Bulimia nervosa (Correct answer)
- Binge eating disorder
- Rumination disorder
Correct answer: Bulimia nervosa
Bulimia nervosa is characterised by recurrent episodes of binge eating followed by compensatory behaviours (self-induced vomiting, laxative misuse, excessive exercise) at least once per week for 3 months. Unlike anorexia nervosa, BMI is typically normal or above normal. NICE recommends CBT-ED as first-line treatment.
Question 4: A patient taking an SSRI presents with agitation, tremor, hyperthermia, hyperreflexia, clonus, and diarrhoea shortly after starting tramadol. What is the most likely diagnosis?
- Neuroleptic malignant syndrome
- Serotonin syndrome (Correct answer)
- Malignant hyperthermia
- Anticholinergic toxicity
Correct answer: Serotonin syndrome
Serotonin syndrome occurs due to excess serotonergic activity, often when two serotonergic drugs are combined (SSRI + tramadol). Features include agitation, tremor, hyperthermia, hyperreflexia, clonus, and diarrhoea. It differs from neuroleptic malignant syndrome (which has rigidity and bradyreflexia). Treatment involves stopping the causative drugs and supportive care.
Question 5: Under the Mental Health Act 1983, what is a Community Treatment Order (CTO)?
- A court order requiring the patient to attend therapy sessions
- A legal framework allowing a detained patient to be discharged from hospital under supervised conditions, with the option of recall if necessary (Correct answer)
- An order preventing the patient from leaving their home
- A voluntary agreement between the patient and their GP
Correct answer: A legal framework allowing a detained patient to be discharged from hospital under supervised conditions, with the option of recall if necessary
A CTO (introduced by the 2007 amendments to the MHA) allows a patient detained under Section 3 to live in the community under specific conditions (e.g., medication compliance, contact with services). The responsible clinician can recall the patient to hospital if conditions are breached or their mental health deteriorates.
Question 6: A 70-year-old man with Alzheimer's disease is prescribed donepezil. What is the mechanism of action of this drug?
- NMDA receptor antagonist
- Acetylcholinesterase inhibitor — it increases acetylcholine levels in the brain (Correct answer)
- Dopamine agonist
- GABA receptor modulator
Correct answer: Acetylcholinesterase inhibitor — it increases acetylcholine levels in the brain
Donepezil is an acetylcholinesterase inhibitor that prevents the breakdown of acetylcholine in the brain, thereby increasing cholinergic transmission. NICE recommends it for mild-to-moderate Alzheimer's disease. Other AChE inhibitors include rivastigmine and galantamine. Memantine (NMDA antagonist) is used for moderate-to-severe disease.
PLAB 1 Psychiatry 2
A 45-year-old man presents after a suicide attempt by overdose.
He has a clear plan, wrote a suicide note, and took steps to avoid being found.
According to UK risk assessment guidelines, which features indicate the highest risk?