OCD Prognosis — MRCPsych Paper B MCQ

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ModerateAnxiety & Stress-Related DisordersOCD PrognosisMRCPsych Paper B

A 40-year-old woman with obsessive-compulsive disorder takes a first-line SSRI regularly at a therapeutic dose for 12 weeks. Approximately what proportion of adults with OCD achieve a clinically meaningful symptomatic response to a single adequate SSRI trial?

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Correct answer: E — 40–60%

The correct answer is E. Approximately 40–60% of adults with OCD achieve a clinically meaningful symptomatic response to a single adequate SSRI trial. Response means substantial improvement rather than complete remission; residual obsessive-compulsive symptoms are common even among responders. NICE recommends SSRIs as first-line pharmacological treatment and allows up to 12 weeks for the therapeutic effect to emerge. Therefore, assessment should consider adherence, dose and treatment duration before concluding that treatment has failed. A markedly lower estimate such as 10–20% understates established SSRI efficacy, whereas rates of 65% or more overestimate the typical response to one medication trial. Near-universal response rates are inconsistent with the substantial proportion who require another SSRI, clomipramine, CBT with exposure and response prevention, or augmentation.

Reference: Abudy A, Juven-Wetzler A, Zohar J. Pharmacological management of treatment-resistant obsessive-compulsive disorder. Drugs. 2011;71:585–596. https://pubmed.ncbi.nlm.nih.gov/21699270/