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Obsessive–compulsive disorder
OCD handwash.jpg
Frequent and excessive hand washing occurs in some people with OCD.
SpecialtyPsychiatry
SymptomsFeel the need to check things repeatedly, perform certain routines repeatedly, have certain thoughts repeatedly
ComplicationsTics, anxiety disorder, suicide
Usual onsetBefore 35 years
CausesUnknown
Risk factorsChild abuse, stress
Diagnostic methodBased on the symptoms
Differential diagnosisAnxiety disorder, major depressive disorder, eating disorders, obsessive–compulsive personality disorder
TreatmentCounseling, selective serotonin reuptake inhibitors, clomipramine
Frequency2.3%

Obsessive–compulsive disorder (OCD) is a mental and behavioral disorder in which a person has intrusive thoughts ("obsessions") and/or feels the need to perform certain routines repeatedly ("compulsions") to an extent where it induces distress or impairs one's general functioning. The condition is associated with tics, anxiety disorders, and a 10–27% risk of attempted suicide along with a general increase in suicidality.

Obsessions are unwanted and persistent thoughts, mental images or urges. These obsessions generate feelings of anxiety, disgust, or unease. Some common obsessions include—but are not limited to—fear of contamination, obsession with symmetry, and unwanted ("intrusive") thoughts about religion, sex, and/or harm.

Compulsions are repeated actions and/or routines that occur in response to obsessions. Some common compulsions include—but are not limited to—excessive hand washing or cleaning, arranging things in a particular way, performing actions according to specific rules, counting, constantly seeking reassurance, and repeatedly checking things. Many adults with this disorder are aware that these behaviors do not make sense, but they perform them anyway to achieve relief from the distress caused by obsessions. These compulsions occur to the degree that daily life is negatively affected; compulsions typically take up at least an hour of each day but, in severe cases, can fill an entire day.

The cause of OCD is unknown. There appear to be some genetic components, and it is more likely for both identical twins to be affected than both fraternal twins. Risk factors include a history of child abuse or other stress-inducing events; some cases have been documented to occur after streptococcal infections. Diagnosis is based on presented symptoms and requires ruling out other drug-related or medical causes, and rating scales such as the Yale–Brown Obsessive Compulsive Scale (Y-BOCS) can be used to assess severity. Other disorders with similar symptoms include generalized anxiety disorder, major depressive disorder, eating disorders, tic disorders, and obsessive–compulsive personality disorder.

Without treatment, OCD often lasts decades. Treatment may involve psychotherapy, such as cognitive behavioral therapy (CBT); pharmacotherapy using antidepressants, such as selective serotonin reuptake inhibitors (SSRIs), serotonin-norepinephrine reuptake inhibitors (SNRIs), or clomipramine; deep brain stimulation (DBS); or any combination of these. CBT for OCD involves increasing exposure to fears and obsessions while preventing the compulsive behavior that would normally accompany obsessions. Contrary to this, metacognitive therapy encourages ritual behaviors in order to alter the relationship to one's thoughts about them. In treating OCD pharmacologically, SSRIs/SNRIs are significantly more effective when used in excess of the usual dosage for depression; however, higher doses may be accompanied by an increase in side-effect burden. Commonly used SSRIs include sertraline, fluoxetine, fluvoxamine, paroxetine, citalopram, and escitalopram. Commonly used SNRIs include venlafaxine and duloxetine. Some patients may have a treatment-resistant (or "treatment-refractory") case of OCD, in which they fail to improve after taking the maximum tolerated dose of multiple SSRIs/SNRIs for at least two months; in such cases, second-line treatment is necessary. The second-line treatments for OCD include clomipramine and antipsychotic augmentation, both of which are associated with more intensive side effects and are therefore not used as primary pharmacological treatments. In the most severe and/or treatment-resistant cases, DBS is used; this type of therapy has shown promising results, but it is still considered experimental due to the limited literature surrounding its methods, success rates, and side effects.

Obsessive–compulsive disorder affects about 2.3% of people at some point in their lives, while rates during any given year are about 1.2%. It is unusual for symptoms to begin after the age of 35, and around 50% of patients experience negative effects to daily life before the age of 20. Males and females are affected about equally, and OCD occurs worldwide. The phrase "obsessive–compulsive" is sometimes used in an informal manner unrelated to OCD to describe someone as being excessively meticulous, perfectionistic, absorbed, or otherwise fixated.

Signs and symptoms

OCD can present with a wide variety of symptoms. Certain groups of symptoms usually occur together; these groups are sometimes viewed as dimensions (or "clusters") that may reflect an underlying process. The standard assessment tool for OCD, the Yale–Brown Obsessive Compulsive Scale (Y-BOCS), has 13 predefined categories of symptoms. These symptoms fit into three to five groupings. A meta-analytic review of symptom structures found a four-factor structure (grouping) to be most reliable. The observed groups included a "symmetry factor," a "forbidden thoughts factor," a "cleaning factor," and a "hoarding factor." The "symmetry factor" correlated highly with obsessions related to ordering, counting, and symmetry, as well as repeating compulsions. The "forbidden thoughts factor" correlated highly with intrusive and distressing thoughts of a violent, religious, or sexual nature. The "cleaning factor" correlated highly with obsessions about contamination and compulsions related to cleaning. The "hoarding factor" only involved hoarding-related obsessions and compulsions and was identified as being distinct from other symptom groupings.

Some OCD subtypes have been associated with improvement in performance on certain tasks, such as pattern recognition (washing subtype) and spatial working memory (obsessive thought subtype). Subgroups have also been distinguished by neuroimaging findings and treatment response. Neuroimaging studies on this have been too few, and the subtypes examined have differed too much to draw any conclusions. On the other hand, subtype-dependent treatment response has been studied, and the hoarding subtype has consistently responded least to treatment.

While OCD is considered a homogeneous disorder from a neuropsychological perspective, many of the putative neuropsychological deficits may be the result of comorbid disorders. For example, adults with OCD have exhibited more symptoms of attention-deficit/hyperactivity disorder (ADHD) and autism spectrum disorder (ASD) than adults without OCD.

Obsessions