Obsessive-Compulsive Disorder (OCD)



  • A behavioral disorder characterized by pathologic obsessions (recurrent intrusive thoughts, ideas, or images) and/or compulsions (repetitive, ritualistic behaviors or mental acts) causing significant distress
  • Not to be confused with obsessive-compulsive (anankastic) personality disorder



  • Three subtypes: child/adolescent-onset (age <18 years), adult-onset (ages 18 to 39 years) and late-onset (age ≥40 years).
  • Child/adolescent-onset in 50% of cases (usually by age 18 years) (1)
  • ~2% lifetime prevalence; slight female predominance when including postpartum OCD

Pediatric Considerations
Consider pediatric autoimmune neuropsychiatric disorders associated with streptococcal (PANDAS) in acute presentation of OCD and tics in children (2).

Geriatric Considerations
Consider neurologic or neurodegenerative disorders in new-onset OCD.

Etiology and Pathophysiology

  • Dysregulation of serotonergic, catecholaminergic and glutamatergic pathways
  • Dysfunction of cortico-striatal-thalamo-cortical (CSTC) circuit, involving the orbitofrontal cortex (OFC) and anterior cingulate cortex (ACC)
  • Brain injury (physical trauma, stroke, etc.)


  • Prevalence rates of 7–15% in first-degree relatives of children/adolescents with OCD
  • ~45–65% of the variance of OCD is explained by genetics

Risk Factors

  • Family history of OCD
  • Advanced paternal and maternal age
  • Coexisting psychiatric disorders, most commonly anxiety disorders and schizophrenia
  • Low serotonin levels (Antipsychotics with greater anti-serotoninergic mechanism, such as clozapine and olanzapine, have been associated with onset of OCD.)
  • Brain insult (i.e., encephalitis, pediatric streptococcal infection, or head injury)
  • History of childhood traumatic events, including social isolation and physical abuse

General Prevention

Early diagnosis and treatment can decrease patient’s distress and impairment.

Commonly Associated Conditions

  • Major depressive disorder
  • Anxiety disorders including panic disorder/phobia/social phobia/generalized anxiety disorder
  • Tourette syndrome/tic syndromes
  • Substance abuse/eating disorder/body dysmorphic disorder
  • Other obsessive-compulsive spectrum disorders including body-focused repetitive behaviors (trichotillomania, excoriation disorder), body dysmorphia, and hoarding disorder

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