OCD — MRCPsych Paper B MCQ

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EasyAnxiety & Stress-Related DisordersOCDMRCPsych Paper B

A 22-year-old man has experienced recurrent thoughts that he might harm a family member for 6 months. He describes the thoughts as unwanted, distressing and inconsistent with his wishes, and he has no intention of acting on them. He avoids being alone with family members and performs mental rituals to neutralise the thoughts. The symptoms interfere with his family life. What is the most appropriate diagnosis?

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Correct answer: C — Obsessive-compulsive disorder

The correct diagnosis is obsessive-compulsive disorder. The recurrent, unwanted and distressing harm thoughts are aggressive obsessions. Avoidance and mental neutralising rituals are compulsive or safety-seeking responses intended to prevent the feared outcome or reduce distress. Their ego-dystonic nature, preserved insight and absence of intent distinguish them from genuine violent wishes. Schizophrenia would require features such as delusions, hallucinations or thought interference rather than unwanted thoughts followed by neutralising rituals. Antisocial personality disorder involves a pervasive pattern of disregard for others, not distress about causing harm. Adjustment disorder requires a clear precipitating stressor, while generalised anxiety disorder causes excessive worry across several domains rather than intrusive taboo thoughts linked to compulsions.

Reference: National Institute for Health and Care Excellence. Obsessive-compulsive disorder and body dysmorphic disorder: treatment (CG31), sections 1.4.1.3 and 1.5.2.2. Published 2005; last reviewed 2024. https://www.nice.org.uk/guidance/cg31/chapter/Recommendations