🔑 Key Learning

  • OCD is characterised by obsessions (distressing thoughts) and/or compulsions (ritualistic behaviours)
    • Compulsions are typically performed to reduce anxiety caused by obsessions
  • Management is guided by severity of functional impairment and includes CBT with Exposure and Response Prevention (ERP) and SSRIs (e.g. fluoxetine, sertraline)

🧠 Definition

  • OCD involves either obsessions, compulsions, or both
  • Symptoms are distressing, intrusive, and time-consuming
  • Patients may recognise the irrational nature of their behaviours but still feel compelled to act on them

🧩 Obsessions vs Compulsions

Obsessions

  • Intrusive thoughts, images, or impulses
  • Repetitive, distressing, and difficult to suppress
  • Often related to fears of harm, contamination, or taboo themes

Compulsions

  • Repetitive behaviours or mental rituals
  • Performed in response to obsessions
  • Aimed at reducing distress or preventing perceived harm
  • Common examples: hand-washing, counting, checking locks, arranging

📋 Diagnosis (ICD-10 Criteria)

Diagnosis requires:

  • Recurrent obsessional thoughts
    • Intrusive, distressing, and internally generated
  • OR recurrent compulsive acts
    • Stereotyped, non-functional, repetitive behaviours
    • Performed to prevent a feared event, even if unrealistic

💊 Management (NICE CKS 2024)

Management is tailored to the level of functional impairment:

Mild impairment

  • First-line: Low-intensity CBT with ERP (Exposure and Response Prevention)
  • If no improvement → escalate to moderate plan

Moderate impairment

  • First-line:
    • High-intensity CBT with ERP
    • OR SSRI (e.g. fluoxetine, sertraline)
    • OR Clomipramine (a TCA) if SSRI unsuitable

Severe impairment

  • First-line:
    • SSRI + High-intensity CBT (with ERP)

📝 Exam Clues & Clinchers

  • Intrusive thoughts about contamination + repeated hand washing →  OCD
  • ERP (exposure + response prevention) is an important behavioural component of CBT used in OCD
  • SSRIs are 1st line pharmacological management of OCD

🔗 Useful Links and References

  NICE CKS- Obsessive Compulsive Disorder [revised February 2024]