Obsessive-Compulsive Disorder (OCD)
General Psychiatry Article Disclaimer
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- DSM-5 criteria or ICD-11 diagnostic requirements are used to structure the Clinical Features and Diagnosis section. The classification system used is selected according to its clarity and suitability for non-specialist learning.
- The criteria are summarised and simplified rather than reproduced in full, while preserving their original diagnostic meaning.
- Where appropriate, a student-friendly pattern-recognition summary is provided to highlight the most clinically and exam-relevant features.
Exam tip (re-psychiatry questions)
- Do not attempt to memorise every DSM-5 or ICD-11 criterion word-for-word. However, it is important to read through the criteria and become familiar with the key symptom clusters, duration thresholds, exclusions, and distinguishing features highlighted in this article.
- Exam questions may not provide every feature required to meet the full diagnostic criteria. Familiarity with the criteria can help one recognise the most likely diagnosis, exclude important alternatives, and narrow the differential diagnosis.
Screening
NICE recommends the following:
| Indications to screen for OCD | Individuals at higher risk of OCD (e.g. those with depression, anxiety, alcohol or substance misuse, body dysmorphic disorder, or eating disorder)
Individuals attending dermatology clinics |
| Screening method | Explore the possibility of comorbid OCD by asking the following direct questions:
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Clinical Features and Diagnosis
High-yield pattern recognition for OCD:
- Presence of obsessions and/or compulsions
- Obsession: recurrent, intrusive and unwanted thoughts, images or urges that cause anxiety / distress (e.g. contamination, fear of harm, unwanted sexual/religious thoughts, need for symmetry/order)
- Compulsion: repetitive behaviours or mental acts performed to reduce anxiety or prevent a feared event (e.g. excessive washing / cleaning, repeated checking, counting, ordering, repeating words/prayers mentally)
- The behaviours are often excessive or not realistically connected to what they are intended to prevent
- Symptoms are time-consuming (>1 hour / day) or cause clinically significant distress or impairment
- Symptoms are not due to a substance/medical condition and are not better explained by another mental disorder
Classic exam pattern: intrusive unwanted thought → marked anxiety → repetitive act to reduce the anxiety
As per the DSM-5 criteria, ALL of the following must be met: [Ref]
| Diagnostic criteria | Criteria description |
|---|---|
| Presence of obsession and/or compulsion | Obsession (both must be present):
Compulsion (both must be present):
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| Impact |
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| Exclusion | The disturbance is not better explained by or attributable to:
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Management
For those who are diagnosed with OCD, it is important to assess the risk of self-harm and suicide (esp. if there is concurrent depression)
Part of the risk assessment should include the impact of their compulsive behaviours on themselves or others
Management depends on 1) age and 2) degree of functional impairment caused by OCD
Adults
| Degree of functional impairment | 1st line management | Step up |
|---|---|---|
| Mild | 1st line: low-intensity CBT, including exposure and response prevention
|
Manage as moderate functional impairment (i.e. CBT or SSRI) |
| Moderate | Offer either (informed by patient’s preference):
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MDT review:
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| Severe | Offer combination therapy of:
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First, switch to a different SSRI or clomipramine
If ineffective → refer to specialist MTD, which may consider
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Do NOT routinely offer anxiolytics to treat OCD. Only consider for short-term use with caution to counter the early activating side effects of SSRIs.
Do NOT use the following to treat OCD:
- TCA that is other than clomipramine
- SNRI (e.g. duloxetine, venlafaxine)
- MOA-I
- Antipsychotics as a monotherapy
Children and Young People (<18 y/o)
| Degree of functional impairment | 1st line management | Step up |
|---|---|---|
| Mild | 1st line: guided self-help + support and information for family or carers | Developmentally adapted CBT that involves the family or carers |
| Moderate to severe | 1st line: developmentally adapted CBT, including exposure and response prevention that involves the family or carers | Consider adding an SSRI to CBT, with specific arrangements for close monitoring |