Psychiatry: disorder groups
Obsessive-compulsive & related disorders
Obsessive-compulsive and related disorders involve unwanted repetitive thoughts and urges and the repetitive behaviours used to relieve them, as in OCD, body dysmorphic disorder, hoarding and hair-pulling. Psychiatrists treat them with exposure-based therapy and specific medication strategies.
Depth by stage, Pre-U → Consultant (details)
What is it?
In obsessive-compulsive disorder (OCD), a person has intrusive, distressing thoughts, images or urges — for example fear of contamination or of causing harm — and feels driven to perform rituals such as washing, checking or counting to reduce the distress. They usually know the fears are excessive but cannot stop.
Related conditions share this pattern of preoccupation and repetition: body dysmorphic disorder (preoccupation with a perceived flaw in appearance), hoarding disorder, trichotillomania (hair pulling), excoriation (skin picking), hypochondriasis/health anxiety (grouped here in ICD-11) and olfactory reference disorder.
OCD can take many hours a day and is often hidden for years out of shame. In religious communities, obsessions can involve worship or purity (sometimes called scrupulosity), which needs a sensitive, culturally informed approach.
Why does a psychiatrist need it?
Psychiatrists must recognise OCD (often missed or mistaken for psychosis or simple anxiety), deliver or arrange exposure and response prevention, use higher-dose SSRIs or clomipramine, and manage resistant cases. Religious-themed obsessions are common in Malaysian practice and need careful collaboration with patients and families.
What level is expected at each stage?
Scale: 1. Aware → 2. Understands → 3. Applies → 4. Masters / Teaches. What the levels mean.
- Pre-UNot expected
- Pre-clinicalAwareAware of OCD as a distinct condition in behavioural science teaching.
- ClinicalUnderstandsCan distinguish obsessions from delusions in principle and name ERP and SSRIs.
- HousemanshipAwareRecognises severe OCD or skin damage from washing in other wards and refers.
- Medical officerUnderstandsAssesses OCD, starts SSRIs and refers for psychological therapy.
- Psych traineeMasters / TeachesDiagnoses the full group, manages resistant OCD and supervises exposure-based treatment.
- Specialist / consultantMasters / TeachesLeads complex and resistant cases and teaches on the spectrum.
What are the key topics?
Conditions
- Obsessive-compulsive disorder (with good/fair, poor or absent insight)
- Body dysmorphic disorder
- Hoarding disorder
- Trichotillomania and excoriation disorder
- Hypochondriasis / health anxiety (ICD-11 grouping)
- Olfactory reference disorder (ICD-11)
- Tic-related OCD and links with Tourette syndrome
Clinical features
- Obsessions vs worries vs delusions vs intrusive thoughts in normal people
- Common themes: contamination, harm, symmetry, sexual or religious themes
- Compulsions, mental rituals, reassurance seeking and avoidance
- Insight levels and their diagnostic significance
- Onset in childhood or early adulthood; course often chronic
Causes
- Cortico-striato-thalamo-cortical circuit models
- Serotonin involvement (response to serotonergic drugs)
- Genetic contribution and family clustering
- Learning theory: rituals maintained by negative reinforcement
- Rare post-infectious onset in children (PANDAS/PANS — debated)
Assessment and treatment
- Yale-Brown Obsessive Compulsive Scale (Y-BOCS) to rate severity
- Exposure and response prevention (ERP), a form of CBT
- SSRIs, often at higher doses and for longer trials; clomipramine
- Antipsychotic augmentation for resistant OCD
- Neurosurgical and neuromodulation options for very severe resistant cases in specialist centres
- Working with religious advisers where obsessions involve worship, with the patient's consent
How is it learned and assessed?
- Undergraduate psychiatry teaching and occasional cases
- MO and trainee outpatient clinics
- MMed Part II clinical examinations; MRCPsych Papers A and B; CASC stations such as OCD history or explaining ERP
Typical textbooks and resources
- Shorter Oxford Textbook of Psychiatry — Oxford University Press
- Cognitive Behaviour Therapy for Psychiatric Problems — Oxford University Press
- The Maudsley Prescribing Guidelines in Psychiatry — Wiley
- NICE guidance on OCD and body dysmorphic disorder — NICE (UK)
Titles are widely used examples; editions change. Use university libraries or legitimate purchases.
Common questions
Is OCD just being very neat?
No. OCD causes real distress and can consume hours a day. The rituals are driven by anxiety and unwanted thoughts, not by enjoying order.
Can religious obsessions be OCD?
Yes. Repeated, distressing doubts about whether prayers or ablutions were done correctly, with repeated checking or redoing, can be a form of OCD. Treatment respects the person's faith and often involves guidance from trusted religious teachers.