Obsessive-compulsive Disorder (OCD)

Obsessive-compulsive disorder (OCD) is a condition characterized by obsessions (recurring and intrusive thoughts, urges, or images) and/or compulsions (repetitive actions the person is compelled to perform) that are time-consuming and associated with functional impairment. Many psychiatric disorders such as depression coexist with OCD. The mean age of onset is about 20 years of age, although the condition can occur earlier. Obsessions present as unwanted thoughts (e.g., fear of contamination) that cause distress and anxiety. The suffering individual attempts to ignore or suppress these thoughts by neutralizing them with another thought or action, which is a compulsion. The individual is driven to perform certain acts or behaviors, which are typically related to an obsession. However, the compulsions are unrealistic or excessive (e.g., washing rituals). The treatment regimen generally includes psychotherapy and pharmacotherapy (with selective serotonin reuptake inhibitors (SSRIs)).

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Obsessive-compulsive disorder (OCD) is a heterogeneous disorder characterized by obsessions and compulsions that impair daily function. 

  • Obsessions:
    • Recurrent thoughts, images, or urges that are intrusive and recognized as unwanted, causing significant anxiety and distress 
    • Some common obsessive concerns include fear of contamination or germs, obsessions with symmetry/order, and thoughts of harm to self or others.
  •  Compulsions:
    • Repetitive behaviors or mental acts that the individual is driven to perform in relation to an obsession
    • Some common compulsive behaviors include repeating words silently, constant checking on something, hoarding, and extreme washing/cleaning.


  • Lifetime prevalence of 2%–3% worldwide 
  • Women have a slightly higher prevalence than men
  • More males are affected in childhood.
  • Mean age of onset is 19.5 years.
  • Onset in childhood or adolescence is frequently associated with a stressful event.
  • Most of those diagnosed with OCD also meet the criteria for other psychiatric disorder(s):
    • ⅔ have a history of another anxiety disorder (e.g., panic disorder).
    • Up to 30% have a lifetime history of tic disorder.
    • High comorbidity with major depressive disorder



  • Accounts for more of the variance in childhood-onset cases
  • Patients who have 1st-degree relatives with OCD are 3–5 times more likely to suffer from OCD themselves.
  • Exact genes involved are still unknown.


  • Pediatric autoimmune neuropsychiatric disorder associated with streptococcal infections (PANDAS):
    • Syndrome associated with OCD brought on by group A streptococcal infection
    • Believed to be an autoimmune reaction to the infection, leading to damage in the basal ganglia
  • Traumatic events (stress)


  • Dysfunction in the cortico-striatal-thalamo-cortical (CSTC) pathway:
    • Deep-brain stimulation in certain areas reduces symptoms of those with therapy-refractory OCD
    • Disruption creates OCD behavior in animal models.
    • New-onset OCD found in those with neurologic lesions (e.g., stroke, traumatic brain injury)
  • Hormonal effects can exacerbate or produce OCD, as seen in premenstrual and/or postpartum periods.
  • Abnormalities in serotonergic, dopamine, and glutamatergic neurotransmission are suspected, though findings are still inconclusive.

Clinical Presentation and Diagnosis

Clinical features

  • Obsessions and compulsions impair activities of daily living because they are time-consuming, intrusive, and cause displeasure.
  • Majority of patients have both obsessions and compulsions.
  • Obsessions may have specific identifiable themes, with related compulsion(s):
    • Fear of contamination (obsession) and resultant behavior of repetitive handwashing (compulsion)
    • Need for order or symmetry (obsession) and arranging items again and again (compulsion)
    • Fear of harm on self or others (obsession), and the compulsion of repeated checking (e.g, making sure doors are locked)
    • Religious obsessions (too much focus on religion) and related compulsion (excessive praying)
    • Sexual obsession (thoughts of improper or disturbing sexual acts) and avoiding interaction with people due to fear of acting on those thoughts
  • Compulsions:
    • Performed to alleviate the stress of the obsession (e.g., wash hands repeatedly to reduce contamination)
    • Acts are often out of proportion or unrealistic, however (e.g., showering for hours to reduce contamination or rearranging items to prevent harm).
  • Course and associated manifestations:
    • Onset is gradual.
    • Strongly associated with suicidal thoughts
    • In the extreme, patients display avoidant behavior (e.g., restricting exposure outside for fear of contamination).
    • Many patients have beliefs of:
      • Grand responsibility and overinflation of threat
      • Perfectionism
    • Patient insight varies as well, with ≤ 4% having no insight (patient is convinced that OCD beliefs are real and true).
  • The Yale-Brown Obsessive Compulsive Scale (Y-BOCS) is a clinician-rated scale for assessing the severity of obsessive and compulsive symptoms.

DSM-V diagnostic criteria for OCD

  • Presence of obsessions, compulsions, or both: 
    • Definition of obsessions:
      • Recurrent thoughts, images, or urges that are intrusive and recognized as unwanted, causing significant anxiety and distress
      • Attempts are made by the individual to avoid, ignore, or suppress such thoughts, images, or urges, or to offset them with another thought or through an action (compulsion).
    • Definition of compulsions:
      • Repetitive behaviors or mental acts that the individual is compelled to perform in response to an obsession or rigid personal rules
      • The behaviors or mental acts are aimed at preventing or reducing anxiety, or preventing an event/situation; however, behaviors are not realistically or proportionately connected to the event/situation.
  • The obsessions and/or compulsions are time-consuming and impair daily activities of life (social or occupational impairment).
  • Drug use or other medical conditions must be ruled out as causes.
  • Symptoms are not better explained by any other psychiatric disorder.



  • CBT: 
    • Uses the technique of exposure and response prevention:
      • Repeated and prolonged exposure to feared situation
      • Abstaining from compulsive behavior
    • Obsessive thoughts without compulsions are more difficult to treat; habituation training or thought stopping is used instead.
    • Thought stopping:
      • A distraction technique in which a sudden sensory stimulus is applied to distract the patient from obsessional thought
      • Patient is taught to identify the obsession (e.g., fear of severe illness from handshakes) and derail it (e.g., patient is instructed to say “stop” when the thought occurs).
  • Group therapy has shown some efficacy.
  • Family education and support are important.


  • SSRIs:
    • Mainstays of drug treatment
    • Higher dosages are often required for treatment of OCD than depression.
  • Tricyclic antidepressants (TCAs) specifically clomipramine, are also good initial treatment options. 
  • Augmentation with antipsychotic medication (e.g., risperidone) has shown efficacy in cases where SSRIs or clomipramine are unsuccessful.
  • Best clinical outcome is combination of SSRIs with behavioral therapy.

Other therapies

  • Deep-brain stimulation: 
    • For treatment-refractory OCD
    • Surgical technique where electrodes are implanted in specific brain locations
    • May improve the efficacy of pharmacotherapy and psychotherapy following successful procedures
    • Adverse effects include development of seizures, infection, and bleeding.
  • Other invasive interventions (experimental):
    • Neurosurgical ablation
    • Transcranial magnetic stimulation

Differential Diagnosis

  • Obsessive-compulsive personality disorder: a preoccupation with orderliness, perfectionism, and mental and interpersonal control at the expense of flexibility and efficiency. The patient follows rigid rules and often has extreme devotion to work at the expense of relationships. The excessive preoccupation is considered to be maladaptive. While the obsessive component is similar to OCD, there are no unwanted urges or thoughts, or irrational recurrent behaviors. 
  • Hoarding disorder: persistent difficulty parting with possessions because of a perceived need to save them. The patient is distressed at the thought of discarding their possessions. Patients can have obsessions (e.g., concerns of harm or feeling of being incomplete) that make hoarding become a compulsive behavior (collecting old newspapers for fear that the information is needed to prevent harm). In these cases, OCD is the diagnosis.
  • Specific phobia: anxiety disorder characterized by significant fear of a particular situation or object. This fear leads to avoidance behavior. Anxiety occurs upon exposure to stimulus but is also triggered even when hearing the name of the stimulus and in anticipation of the stimulus. Compared with OCD, specific phobia is not associated with rituals or repetitive acts.
  • Tourette syndrome: tics and related diseases represent a set of neurobehavioral disorders of childhood that are characterized by sudden and repeated muscle movements sometimes accompanied by sounds or vocalizations. Tourette syndrome is a severe form with symptoms lasting more than 1 year and involving both motor and vocal tics. These repetitive behaviors are not compulsions as they are not aimed at neutralizing obsessions. Obsessive-compulsive disorder and Tourette syndrome frequently co-occur.


  1. Abramowitz, J. (2021). Psychotherapy for obsessive-compulsive disorder in adults. UpToDate. Retrieved June 13, 2021, from https://www.uptodate.com/contents/psychotherapy-for-obsessive-compulsive-disorder-in-adults
  2. Raj KS, Williams N, Battista C. (2021). Obsessive-compulsive disorder & related disorders. Papadakis MA, McPhee SJ, Rabow MW (Eds.), Current Medical Diagnosis & Treatment 2021. McGraw-Hill. https://accessmedicine.mhmedical.com/content.aspx?bookid=2957&sectionid=249375264
  3. Sadock BJ, Sadock VA, Ruiz, P. (2014). Kaplan and Sadock’s synopsis of psychiatry: Behavioral sciences/clinical psychiatry (11th ed.). Chapter 10, Obsessive-compulsive and related disorders, pages 418-427. Philadelphia, PA: Lippincott Williams and Wilkins.
  4. Simpson, H. (2021) Obsessive-compulsive disorder in adults: epidemiology, pathogenesis, clinical manifestations, course and diagnosis. UpToDate. Retrieved June 12, 2021, from https://www.uptodate.com/contents/obsessive-compulsive-disorder-in-adults-epidemiology-pathogenesis-clinical-manifestations-course-and-diagnosis
  5. Simpson H. (2021) Pharmacotherapy for obsessive-compulsive disorder in adults. UpToDate. Retrieved June 13, 2021, from https://www.uptodate.com/contents/pharmacotherapy-for-obsessive-compulsive-disorder-in-adults

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