Light Therapy for SAD — MRCPsych Paper B MCQ

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EasyMood DisordersLight Therapy for SADMRCPsych Paper B

Which depressive presentation has the longest-established and most directly studied evidence base for bright light therapy?

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

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Correct answer: D — Depression with a recurrent winter seasonal pattern

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

The correct answer is B. Bright light therapy has its longest-established and most directly studied role in depressive episodes with a recurrent winter seasonal pattern. Meta-analysis supports benefit over placebo in seasonal affective disorder, whereas evidence in non-seasonal unipolar and bipolar depression is newer, lower quality or less conclusive. NICE nevertheless advises that patients with winter depression should be told that efficacy remains uncertain. Therefore, this answer concerns the relative evidence base rather than implying guaranteed efficacy or routine NHS provision. A is incorrect because evidence is not equal across all depression. Light therapy has no specific established role in psychotic depression (C). Bipolar depression (D) has some adjunctive evidence but requires further study. Treatment resistance alone (E) is not a defining indication. ([nice.org.uk](https://www.nice.org.uk/guidance/ng222/chapter/Recommendations?utm_source=openai))

Reference: Pjrek E, et al. The Efficacy of Light Therapy in the Treatment of Seasonal Affective Disorder: A Meta-Analysis of Randomized Controlled Trials. Psychotherapy and Psychosomatics. 2020;89(1):17–24. https://pubmed.ncbi.nlm.nih.gov/31574513/