PLAB Psychiatry & Mental Health 1 — Questions and Answers
Question 1: A 28-year-old presents with persistent low mood, anhedonia, disturbed sleep, and poor concentration lasting 3 months. Which diagnosis is most likely?
- Major depressive disorder (Correct answer)
- Bipolar disorder
- Dysthymia
- Adjustment disorder
Correct answer: Major depressive disorder
Major depressive disorder requires depressed mood or anhedonia plus at least four additional symptoms persisting for a minimum of two weeks.
Question 2: A 45-year-old with schizophrenia on haloperidol for 3 years develops involuntary repetitive movements of the mouth and tongue. What is the most likely diagnosis?
- Acute dystonia
- Tardive dyskinesia (Correct answer)
- Akathisia
- Drug-induced parkinsonism
Correct answer: Tardive dyskinesia
Tardive dyskinesia is a late-onset movement disorder caused by prolonged antipsychotic use, characteristically involving orofacial repetitive movements.
Question 3: A 19-year-old male presents with auditory hallucinations, delusions of persecution, and social withdrawal for 6 months. What is the most appropriate first-line pharmacological treatment?
- Lithium carbonate
- Fluoxetine
- Risperidone (Correct answer)
- Diazepam
Correct answer: Risperidone
Atypical antipsychotics such as risperidone are recommended as first-line pharmacological treatment for schizophrenia.
Question 4: Which feature most clearly distinguishes a manic episode from a hypomanic episode in bipolar disorder?
- Elevated or irritable mood
- Grandiosity
- Decreased need for sleep
- Marked functional impairment or need for hospitalization (Correct answer)
Correct answer: Marked functional impairment or need for hospitalization
Mania, unlike hypomania, causes marked functional impairment, may require hospitalization, and can include psychotic features.
Question 5: A 32-year-old woman presents with recurrent binge eating followed by self-induced vomiting. Her BMI is 22. What is the most likely diagnosis?
- Anorexia nervosa binge-purge subtype
- Bulimia nervosa (Correct answer)
- Binge eating disorder
- Avoidant/restrictive food intake disorder
Correct answer: Bulimia nervosa
Bulimia nervosa is characterized by recurrent binge-purge cycles with a normal or near-normal BMI, distinguishing it from anorexia nervosa.
Question 6: A patient on lithium presents with coarse tremor, vomiting, confusion, and ataxia. What is the most important immediate step?
- Add propranolol to manage the tremor
- Measure serum lithium level urgently (Correct answer)
- Switch to valproate immediately
- Increase fluid intake and continue lithium
Correct answer: Measure serum lithium level urgently
The constellation of neurological and gastrointestinal symptoms suggests lithium toxicity; an urgent serum lithium level is essential to confirm and guide management.
Question 7: A 40-year-old alcohol-dependent man presents 48 hours after his last drink with agitation, tremor, diaphoresis, and tachycardia. What is the most serious complication to anticipate?
- Wernicke's encephalopathy
- Hepatic encephalopathy
- Delirium tremens with seizures (Correct answer)
- Korsakoff psychosis
Correct answer: Delirium tremens with seizures
Delirium tremens typically emerges 48–72 hours after alcohol cessation and carries significant mortality without prompt treatment with benzodiazepines.
PLAB Psychiatry & Mental Health 1
A 28-year-old presents with persistent low mood, anhedonia, disturbed sleep, and poor concentration lasting 3 months.
Which diagnosis is most likely?