SSRI Early Side Effects — MRCPsych Paper B MCQ

Instant feedback + full explanation. One question, done properly.

EasyMood DisordersSSRI Early Side EffectsMRCPsych Paper B

A 38-year-old woman with depression is reviewed 10 days after starting sertraline 50 mg daily. She has taken only the prescribed dose and reports nausea, loose stools and difficulty sleeping. She is afebrile, with a normal pulse, and has no confusion, agitation, tremor, clonus, muscle rigidity or rash. What is the most likely explanation?

Educational content. Not a substitute for clinical judgement or local policy.

Reveal the answer and explanation

Correct answer: A — Expected early adverse effects of sertraline

The correct answer is A. Nausea, diarrhoea and insomnia are very common adverse effects of sertraline and may diminish as treatment continues. Their onset shortly after initiation, with use at the prescribed dose and normal examination findings, supports expected early adverse effects. Serotonin syndrome would usually involve a combination of mental-state change, autonomic disturbance and neuromuscular abnormalities such as agitation, sweating, hyperthermia, tremor, hyperreflexia or clonus. Overdose is excluded by the dosing history and would more often produce features such as somnolence, tachycardia, tremor or agitation. Immediate hypersensitivity would suggest urticaria, angioedema or respiratory symptoms. Clinically significant hyponatraemia more typically causes headache, confusion, weakness, unsteadiness or seizures.

Reference: Electronic Medicines Compendium, Sertraline 50 mg film-coated tablets, Summary of Product Characteristics, sections 4.4, 4.8 and 4.9, updated 28 January 2026. https://www.medicines.org.uk/emc/product/14327/smpc