Table of Contents
Overview – Obsessive Compulsive Disorder
Obsessive Compulsive Disorder (OCD) is a chronic psychiatric condition characterised by intrusive, anxiety-provoking thoughts (obsessions) and repetitive behaviours or mental acts (compulsions) aimed at reducing distress. These behaviours are time-consuming, disruptive, and often recognised by the individual as irrational—leading to further emotional distress. OCD is highly disabling when untreated, but effective interventions exist, including psychological therapy and pharmacological management.
Definition
OCD is defined by the presence of:
- Obsessions: unwanted, intrusive thoughts, images, or urges that cause significant anxiety or distress.
- Compulsions: repetitive behaviours or mental acts performed in response to an obsession, aimed at neutralising distress or preventing a feared event, even if the action is clearly excessive or not logically connected.
Aetiology
Neurobiology
- Dysregulation of serotonin pathways → ↓ sensitivity of serotonin receptors
- Supported by therapeutic efficacy of SSRIs
Pathophysiology
- Functional neuroimaging suggests hyperactivity in the orbitofrontal cortex, anterior cingulate cortex, and caudate nucleus
- Serotonergic dysregulation plays a key role in both symptom generation and treatment response
Clinical Features
- Recurrent intrusive thoughts (e.g. contamination, harm, symmetry)
- Time-consuming compulsions (e.g. hand-washing, checking, counting, hoarding)
- Insight usually preserved: most patients recognise irrationality of their behaviours
- Marked distress, social isolation, or occupational disruption
- Associated with emotional, financial, and interpersonal impairment
DSM-5 Diagnostic Criteria
A) Presence of obsessions, compulsions, or both:
- Obsessions:
- Intrusive, persistent, unwanted thoughts or urges that cause distress
- Attempted suppression or neutralisation via other thoughts/actions
- Compulsions:
- Repetitive behaviours or mental acts (e.g. checking, praying, counting)
- Intended to reduce distress or prevent dreaded outcomes, but unrealistic or excessive
B) Obsessions/compulsions are time-consuming (e.g. >1 hr/day) or cause significant distress or impairment in functioning
C) Symptoms not attributable to substance or medical condition
D) Not better explained by another mental disorder (e.g. body dysmorphic disorder, hoarding disorder)
Differential Diagnosis
- Generalised anxiety disorder
- Major depressive disorder (with rumination)
- Psychotic disorders (e.g. schizophrenia with bizarre delusions)
- Autism spectrum disorders (with stereotyped behaviours)
- Tic disorders (simple motor/vocal tics may resemble compulsions)
Management
Psychological
- Cognitive Behavioural Therapy (CBT) with Exposure and Response Prevention (ERP):
- Patients are exposed to feared stimuli while refraining from compulsive behaviours
- Underlying cognitive distortions are challenged
Pharmacological
- SSRIs/SNRIs (e.g. fluoxetine, sertraline, venlafaxine)
- Higher doses and longer trials (12–16 weeks) required compared to depression
- Clomipramine: a tricyclic antidepressant, second-line due to side effects
- Augmentation: low-dose atypical antipsychotics (e.g. risperidone) for refractory cases
Complications
- Social isolation and poor quality of life
- Economic burden from impaired work function
- Increased risk of comorbid depression or suicidal ideation
- Chronic and relapsing course; treatment-resistant in many cases
Summary – Obsessive Compulsive Disorder
Obsessive Compulsive Disorder is a chronic and often debilitating condition characterised by intrusive obsessions and compulsive behaviours. Although patients typically recognise the irrational nature of their symptoms, they struggle to suppress them, leading to significant distress and impairment. First-line treatment includes cognitive behavioural therapy with exposure and response prevention, alongside high-dose SSRIs or clomipramine. For a broader context, see our Psychiatry & Mental Health Overview page.