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St John's Wort — MRCPsych Paper B MCQ

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ModerateMood DisordersSt John's WortMRCPsych Paper B

An adult woman with less severe depression asks whether she should start an over-the-counter St John's wort preparation. According to NICE guidance, what is the most appropriate advice?

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Reveal the answer and explanation

Correct answer: A — Its use should not be advised because dosing and persistence of effect are uncertain, preparations vary, and serious drug interactions can occur

Explanation lettering: B = shown as A · C = shown as B · D = shown as C · A = shown as D

B is correct. NICE acknowledges some evidence that St John's wort may benefit less severe depression, but advises healthcare professionals not to prescribe or recommend it. The reasons are uncertainty about appropriate dosing and persistence of benefit, variation in the nature and potency of available preparations, and potentially serious drug interactions. Important examples include interactions with hormonal contraceptives, anticoagulants and anticonvulsants. It is therefore not a NICE-recommended first-line treatment, excluding A. NICE does not establish that it is more effective than SSRIs, excluding C. Clinically important interactions mean D is unsafe. Variation between preparations directly contradicts E. The original keyed answer was correct, but the unsupported claim that NICE's recommendation is based on a general “lack of regulation” has been removed.

Reference: National Institute for Health and Care Excellence. Depression in adults: treatment and management (NG222), recommendation 1.4.38: Use of St John's Wort. 2022; page current 2026. https://www.nice.org.uk/guidance/ng222/chapter/recommendations