Obsessive-Compulsive Disorder (OCD)

Definition | Aetiology | Pathophysiology | Risk factors | Signs and symptoms | Investigations | Management

Definition

Obsessive-Compulsive Disorder (OCD) is a chronic mental health condition characterised by intrusive, unwanted thoughts (obsessions) and repetitive behaviours or mental acts (compulsions) performed to reduce distress.

Aetiology

• Genetic factors: strong hereditary component, familial clustering.
• Neurobiological factors: dysregulation of serotonin pathways in the cortico-striatal-thalamo-cortical (CSTC) circuit.
• Psychosocial factors: childhood trauma, stressful life events, perfectionistic traits.
• Infections: Paediatric Autoimmune Neuropsychiatric Disorders Associated with Streptococcal infections (PANDAS) in some cases.

Pathophysiology

• Overactivity in the cortico-striatal-thalamo-cortical (CSTC) loop leading to repetitive thoughts and behaviours.
• Serotonin dysregulation contributing to compulsive behaviours.
• Hyperactivity in the orbitofrontal cortex and caudate nucleus.

Risk factors

• Family history of OCD or other anxiety disorders.
• History of childhood trauma or adverse experiences.
• Perfectionistic or rigid personality traits.
• High levels of chronic stress.
• Comorbid conditions (e.g., tic disorders, depression, anxiety disorders).

Signs and symptoms

• Obsessions (intrusive thoughts):
  • Contamination fears (e.g., fear of germs, dirt).
  • Symmetry/orderliness concerns.
  • Unwanted aggressive, sexual, or religious thoughts.
  • Fear of harm to self or others.
• Compulsions (repetitive behaviours or mental acts):
  • Excessive handwashing or cleaning.
  • Checking behaviours (e.g., ensuring doors are locked, stove is off).
  • Counting, tapping, or repeating words silently.
  • Arranging objects in a specific order.
• Significant distress and impairment in daily functioning.

Investigations

• Clinical assessment: comprehensive psychiatric history and mental state examination.
• Structured diagnostic tools: Yale-Brown Obsessive Compulsive Scale (Y-BOCS).
• Collateral history: from family members or caregivers.
• Blood tests: if secondary causes suspected (e.g., TFTs for underlying endocrine conditions).
• Neuroimaging (MRI/CT): only if organic pathology suspected.

Management

1. Psychological interventions:

• Cognitive Behavioural Therapy (CBT) with Exposure and Response Prevention (ERP) as first-line treatment.
• Mindfulness-based cognitive therapy for distress management.
• Family therapy if OCD impacts household dynamics.

2. Pharmacological management:

• Selective serotonin reuptake inhibitors (SSRIs) (e.g., fluoxetine, fluvoxamine, sertraline) at higher doses than used for depression.
• Clomipramine (a tricyclic antidepressant) for severe or treatment-resistant OCD.
• Augmentation with atypical antipsychotics (e.g., risperidone, aripiprazole) in treatment-resistant cases.

3. Social and lifestyle interventions:

• Support groups for individuals with OCD and their families.
• Stress management techniques (e.g., relaxation therapy, mindfulness).
• Workplace or academic accommodations to reduce distress.

4. Referral:

• Psychologist: for CBT and exposure therapy.
• Psychiatrist: for complex or treatment-resistant OCD requiring medication.
• Specialist OCD services: if severe or refractory symptoms persist despite treatment.

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