Obsessive–compulsive disorder (OCD, F42 in ICD-10) is a mental disorder in which a person feels the need to perform certain routines repeatedly (called “compulsions”), or has certain thoughts repeatedly (called “obsessions”). The person is unable to control either the thoughts or activities for more than a short period of time. Common compulsions include hand washing, counting of things, and checking to see if a door is locked. Some may have difficulty throwing things out. These activities occur to such a degree that the person’s daily life is negatively affected, often taking up more than an hour a day. Most adults realize that the behaviors do not make sense. The condition is associated with tics, anxiety disorder, and an increased risk of suicide.

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

Treatment involves psychotherapy, such as cognitive behavioral therapy (CBT), and sometimes antidepressants, such as selective serotonin reuptake inhibitors (SSRIs) or clomipramine. CBT for OCD involves increasing exposure to what causes the problems while not allowing the repetitive behavior to occur. Contrary to this, Metacognitive therapy encourages the ritual behaviors as to alter the relationship to ones thoughts about them. While clomipramine appears to work as well as SSRIs, it has greater side effects and thus is typically reserved as a second-line treatment. Atypical antipsychotics may be useful when used in addition to an SSRI in treatment-resistant cases but are also associated with an increased risk of side effects. Without treatment, the condition often lasts decades.

Obsessive–compulsive disorder affects about 2.3% of people at some point in their lives. Rates during a given year are about 1.2%, and it occurs worldwide It is unusual for symptoms to begin after the age of 35, and half of people develop problems before 20. Males and females are affected about equally. 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.

While OCD has been considered a homogeneous disorder from a neuropsychological perspective, many of the putative neuropsychological deficits may be due to comorbid disorders. Furthermore, some 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.

Obsessions

Obsessions are thoughts that recur and persist despite efforts to ignore or confront them. People with OCD frequently perform tasks, or compulsions, to seek relief from obsession-related anxiety. Within and among individuals, the initial obsessions, or intrusive thoughts, vary in their clarity and vividness. A relatively vague obsession could involve a general sense of disarray or tension accompanied by a belief that life cannot proceed as normal while the imbalance remains. A more intense obsession could be a preoccupation with the thought or image of someone close to them dying or intrusions related to “relationship rightness“. Other obsessions concern the possibility that someone or something other than oneself—such as God, the devil, or disease—will harm either the person with OCD or the people or things that the person cares about. Other individuals with OCD may experience the sensation of invisible protrusions emanating from their bodies or have the feeling that inanimate objects are ensouled.

Some people with OCD experience sexual obsessions that may involve intrusive thoughts or images of “kissing, touching, fondling, oral sex, anal sex, intercourse, incest, and rape” with “strangers, acquaintances, parents, children, family members, friends, coworkers, animals, and religious figures”, and can include “heterosexual or homosexual content” with persons of any age. As with other intrusive, unpleasant thoughts or images, some disquieting sexual thoughts at times are normal, but people with OCD may attach extraordinary significance to the thoughts. For example, obsessive fears about sexual orientation can appear to the person with OCD, and even to those around them, as a crisis of sexual identity. Furthermore, the doubt that accompanies OCD leads to uncertainty regarding whether one might act on the troubling thoughts, resulting in self-criticism or self-loathing.

Most people with OCD understand that their notions do not correspond with reality; however, they feel that they must act as though their notions are correct. For example, an individual who engages in compulsive hoarding might be inclined to treat inorganic matter as if it had the sentience or rights of living organisms, while accepting that such behavior is irrational on a more intellectual level. There is a debate as to whether or not hoarding should be considered with other OCD symptoms.

OCD sometimes manifests without overt compulsions, referred to as Primarily Obsessional OCD. OCD without overt compulsions could, by one estimate, characterize as many as 50 percent to 60 percent of OCD cases.

Compulsions

Some people with OCD perform compulsive rituals because they inexplicably feel they have to, while others act compulsively so as to mitigate the anxiety that stems from particular obsessive thoughts. The person might feel that these actions somehow either will prevent a dreaded event from occurring or will push the event from their thoughts. In any case, the individual’s reasoning is so idiosyncratic or distorted that it results in significant distress for the individual with OCD or for those around them. Excessive skin picking, hair-pulling, nail biting, and other body-focused repetitive behavior disorders are all on the obsessive–compulsive spectrum. Some individuals with OCD are aware that their behaviors are not rational, but feel compelled to follow through with them to fend off feelings of panic or dread.

Some common compulsions include hand washing, cleaning, checking things (e.g., locks on doors), repeating actions (e.g., turning on and off switches), ordering items in a certain way, and requesting reassurance. Compulsions are different from tics (such as touching, tapping, rubbing, or blinking) and stereotyped movements (such as head banging, body rocking, or self-biting), which usually are not as complex and are not precipitated by obsessions. It can sometimes be difficult to tell the difference between compulsions and complex tics. About 10% to 40% of individuals with OCD also have a lifetime tic disorder.

People rely on compulsions as an escape from their obsessive thoughts; however, they are aware that the relief is only temporary, that the intrusive thoughts will soon return. Some people use compulsions to avoid situations that may trigger their obsessions. Although some people do certain things over and over again, they do not necessarily perform these actions compulsively. For example, bedtime routines, learning a new skill, and religious practices are not compulsions. Whether or not behaviors are compulsions or mere habit depends on the context in which the behaviors are performed. For example, arranging and ordering DVDs for eight hours a day would be expected of one who works in a video store, but would seem abnormal in other situations. In other words, habits tend to bring efficiency to one’s life, while compulsions tend to disrupt it.

In addition to the anxiety and fear that typically accompanies OCD, sufferers may spend hours performing such compulsions every day. In such situations, it can be hard for the person to fulfill their work, family, or social roles. In some cases, these behaviors can also cause adverse physical symptoms. For example, people who obsessively wash their hands with antibacterial soap and hot water can make their skin red and raw with dermatitis.

People with OCD can use rationalizations to explain their behavior; however, these rationalizations do not apply to the overall behavior but to each instance individually. For example, a person compulsively checking the front door may argue that the time taken and stress caused by one more check of the front door is much less than the time and stress associated with being robbed, and thus checking is the better option. In practice, after that check, the person is still not sure and deems it is still better to perform one more check, and this reasoning can continue for as long as necessary.

Insight

The DSM-V contains three specifiers for the level of insight in OCD. Good or fair insight is characterized by the acknowledgment that obsessive-compulsive beliefs are or may not be true. Poor insight is characterized by the belief that obsessive-compulsive beliefs are probably true. Absence of insight makes obsessive-compulsive beliefs delusional thoughts, and occurs in about 4% of people with OCD.

Overvalued ideas

Some people with OCD exhibit what is known as overvalued ideas. In such cases, the person with OCD will truly be uncertain whether the fears that cause them to perform their compulsions are irrational or not. After some discussion, it is possible to convince the individual that their fears may be unfounded. It may be more difficult to do ERP therapy on such people because they may be unwilling to cooperate, at least initially. There are severe cases in which the person has an unshakable belief in the context of OCD that is difficult to differentiate from psychotic disorders.

Cognitive performance

Though it was once believed to be associated with above-average intelligence, this does not appear to be the case. A 2013 review reported that people with OCD have mild but wide-ranging cognitive deficits; significantly regarding spatial memory, to a lesser extent with verbal memory, fluency, executive function, and processing speed, while auditory attention was not significantly affected.^[33] People with OCD show impairment in formulating an organizational strategy for coding information, set-shifting, and motor and cognitive inhibition.

Specific subtypes of symptom dimensions in OCD have been associated with specific cognitive deficits. For example, the results of one meta-analysis comparing washing and checking symptoms reported that washers outperformed checkers on eight out of ten cognitive tests. The symptom dimension of contamination and cleaning may be associated with higher scores on tests of inhibition and verbal memory.

Children

Approximately 1–2% of children are affected by OCD. Obsessive–compulsive disorder symptoms tend to develop more frequently in children that are 10–14 years of age, with males displaying symptoms at an earlier age and a more severe level than the females. In children, symptoms can be grouped into at least four types.

Associated conditions

People with OCD may be diagnosed with other conditions, as well as or instead of OCD, such as the aforementioned obsessive–compulsive personality disorder, major depressive disorder, bipolar disorder, generalized anxiety disorder, anorexia nervosa, social anxiety disorder, bulimia nervosa, Tourette syndrome, transformation obsession, autism spectrum disorder, attention deficit hyperactivity disorder, dermatillomania (compulsive skin picking), body dysmorphic disorder and trichotillomania (hair pulling). More than 50 percent of people experience suicidal tendencies, and 15 percent have attempted suicide. Depression, anxiety and prior suicide attempts increase the risk of future suicide attempts.

Individuals with OCD have also been found to be affected by delayed sleep phase syndrome at a substantially higher rate than the general public. Moreover, severe OCD symptoms are consistently associated with greater sleep disturbance. Reduced total sleep time and sleep efficiency have been observed in people with OCD, with delayed sleep onset and offset and an increased prevalence of delayed sleep phase disorder.

Behaviorally, there is some research demonstrating a link between drug addiction and the disorder as well. For example, there is a higher risk of drug addiction among those with any anxiety disorder (possibly as a way of coping with the heightened levels of anxiety), but drug addiction among people with OCD may serve as a type of compulsive behavior and not just as a coping mechanism. Depression is also extremely prevalent among people with OCD. One explanation for the high depression rate among OCD populations was posited by Mineka, Watson and Clark (1998), who explained that people with OCD (or any other anxiety disorder) may feel depressed because of an “out of control” type of feeling.

Someone exhibiting OCD signs does not necessarily have OCD. Behaviors that present as (or seem to be) obsessive or compulsive can also be found in a number of other conditions as well, including obsessive–compulsive personality disorder (OCPD), autism spectrum disorder, disorders where perseveration is a possible feature (ADHD, PTSD, bodily disorders or habit problems) or sub-clinically.

Some with OCD present with features typically associated with Tourette’s syndrome, such as compulsions that may appear to resemble motor tics; this has been termed “tic-related OCD” or “Tourettic OCD”.

OCD frequently co-occurs with both bipolar disorder and major depressive disorder. Between 60–80% of those with OCD experience a major depressive episode in their lifetime. Comorbidity rates have been reported at between 19–90% due to methodological differences. Between 9–35% of those with bipolar disorder also have OCD, compared to the 1–2% in the general population. Around 50% of those with OCD experience cyclothymic traits or hypomanic episodes. OCD is also associated with anxiety disorders. Lifetime comorbidity for OCD has been reported at 22% for specific phobia, 18% for social anxiety disorder, 12% for panic disorder, and 30% for generalized anxiety disorder. The comorbidity rate for OCD and ADHD has been reported as high as 51%.

Causes

The cause is unknown. Both environmental and genetic factors are believed to play a role. Risk factors include a history of child abuse or other stress-inducing event.

Genetics

There appear to be some genetic components with identical twins more often affected than non-identical twins. Further, individuals with OCD are more likely to have first-degree family members exhibiting the same disorders than do matched controls. In cases where OCD develops during childhood, there is a much stronger familial link in the disorder than cases in which OCD develops later in adulthood. In general, genetic factors account for 45–65% of the variability in OCD symptoms in children diagnosed with the disorder. A 2007 study found evidence supporting the possibility of a heritable risk for OCD.

A mutation has been found in the human serotonin transporter gene, hSERT, in unrelated families with OCD.

A systematic review found that while neither allele was associated with OCD overall, in caucasians the L allele was associated with OCD. Another meta analysis observed an increased risk in those with the homozygous S allele, but found the LS genotype to be inversely associated with OCD.

A genome wide association study found OCD to be linked with SNPs near BTBD3 and two SNPs in DLGAP1 in a trio-based analysis, but no SNP reached significance when analyzed with case-control data.

One meta analysis found a small but significant association between a polymorphism in SLC1A1 and OCD.

The relationship between OCD and COMT has been inconsistent, with one meta analysis reporting a significant association, albeit only in men, and another meta analysis reporting no association.

It has been postulated by evolutionary psychologists that moderate versions of compulsive behavior may have had evolutionary advantages. Examples would be moderate constant checking of hygiene, the hearth or the environment for enemies. Similarly, hoarding may have had evolutionary advantages. In this view OCD may be the extreme statistical “tail” of such behaviors, possibly due to a high amount of predisposing genes.

Autoimmune

A controversial hypothesis is that some cases of rapid onset of OCD in children and adolescents may be caused by a syndrome connected to Group A streptococcal infections, known as pediatric autoimmune neuropsychiatric disorders associated with streptococcal infections (PANDAS).

A review of studies examining anti-basal ganglia antibodies in OCD found an increased risk of having anti-basal ganglia antibodies in those with OCD versus the general population.