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date: 21 October 2017

Obsessive-Compulsive Disorder

Summary and Keywords

Obsessive-compulsive disorder (OCD) is one of the most destructive psychological disorders. Its symptoms often interfere with work or school, interpersonal relationships, and with activities of daily living (e.g., driving, using the bathroom). Moreover, the psychopathology of OCD is seemingly complex: sufferers battle ubiquitous unwanted thoughts, doubts, and images that, while senseless on the one hand, are perceived as signs of danger on the other hand. The thematic variation and elaborate relations between behavioral and cognitive signs and symptoms can be perplexing to even the most experienced of observers. Cognitive-behavioral models of OCD explain these phenomena and account for their heterogeneity. These models also have implications for how OCD is treated using exposure and response prevention, which research indicates are effective short- and long-term interventions.

Keywords: OCD, obsessions, compulsions, cognitive-behavior therapy, obsessive-compulsive disorder, exposure therapy, rituals

Signs and Symptoms of Obsessive-Compulsive Disorder


Obsessions are thoughts, images, impulses, doubts, and ideas that are experienced as unwanted and intrusive (i.e., difficult to control), anxiety or guilt-provoking, or repugnant and senseless (American Psychiatric Association, 2013). Although highly individualized, the general themes of obsessions can be grouped into categories such as contamination, responsibility for harm, doubt, unacceptable thoughts about sex, violence, and blasphemy, and the need for order or symmetry.

Obsessions are experienced as unwanted in that they intrude into consciousness (often triggered by external stimuli) and are not the types of thoughts one would expect of him or herself. They are also accompanied by the sense that they must be “dealt with,” neutralized, or avoided. The motivation to resist is activated by the fear that if something is not done about the thoughts, disastrous consequences will occur. Table 1 includes examples of common obsessions.

Table 1. Examples of Obsessions Reported Clinic Patients with OCD




  • What if I get rabies from driving over a dead animal on the street?

  • I used a public bathroom; what if I have someone else’s germs on me?

Responsibility for harm

  • By mistake, I might have kissed someone other than my spouse without realizing it

  • What if I left the door unlocked, and someone will break into my home?

  • What if I called my friend a racial slur without realizing it?


  • Odd numbers are “incorrect.”

  • The books must be evenly placed on the shelf or else I will have bad luck

Unacceptable thoughts with immoral, sexual, or violent content

  • Blasphemous thought

  • Image of my grandparents having sex

  • Thought about stabbing my husband in his sleep


Compulsive rituals are senseless excessive behaviors performed in response to obsessions and often according to self-imposed “rules” (American Psychiatric Association, 2013). Categories of rituals include de-contamination (washing/cleaning), checking (including asking others for reassurance), repeating routine activities (e.g., going back and forth through doorways), arranging items, and mental rituals. Compulsions are deliberate and purposeful, in contrast to behaviors such as tics, which are more mechanical. Rituals in OCD also serve to reduce obsessional distress, in contrast to repetitive behaviors in addictive or impulse-control problems (e.g., hair pulling), which are carried out because they produce gratification (APA, 2013). Table 2 presents examples of common compulsive rituals.

Table 2. Examples of Compulsive Rituals Reported Clinic Patients with OCD




  • Hand-washing for 45 minutes in response to using the bathroom

  • Wiping down all objects brought into the house for fear of germs from recently applied pesticides on an adjacent lawn


  • Driving back to re-check that no accidents were caused at the intersection

  • Returning home after seeing a fire engine to make sure the house wasn’t on fire

Repeating routine activities

  • Going through a doorway over and over to prevent bad luck

  • Retracing one’s steps to make sure that no mistakes were made


  • Saying the word “left” whenever one hears the word “right”

  • Re-arranging the books on the bookshelf until they are “just right”

Mental rituals

  • Cancelling a “bad” thought by thinking of a “good” thought

  • Excessive praying to prevent feared disastrous consequences

As Table 2 shows, compulsions can be overt or covert. Additional examples of covert (mental) rituals include repetition of phrases or prayers in a particular manner, and mentally analyzing one’s previous conversations to make sure one has not said anything offensive. Most people with OCD also engage in behaviors in response to obsessions, such as distraction and thought suppression that are neither rule-bound nor repetitive. Such rituals can be remarkably subtle, yet all such behaviors serve to neutralize obsessional thoughts or fears. The following examples illustrate neutralization strategies.

  • A woman clutched the steering wheel tightly in response to unwanted thoughts of steering the car off the road.

  • A man with obsessional thoughts of his child dying tried to suppress and dismiss such images (thought suppression).

  • A woman with obsessions about harming her mother confessed these thoughts to her mother whenever they came to mind. She explained, “If I tell mother that I’m thinking about hurting her, she’ll be ready to stop me if I act out.”

Many people with OCD attempt to gain certainty that obsessional doubts are invalid. This might involve overt (e.g., asking questions) or covert (checking for signs of sexual arousal in response to inappropriate stimuli) behavior, although the typical style is asking questions repeatedly.


Avoidance behavior is observed in most people with OCD and is performed to prevent feared consequences as featured in obsessional thoughts (Abramowitz & Jacoby, 2015). For example, one woman avoided using knives because they evoked obsessional thoughts of impulsively stabbing people. Other patients engage in avoidance so that they do not have to carry out compulsive rituals. For instance a woman avoided driving past construction sites because her obsessional fears of contamination from construction materials led to time-consuming compulsive cleaning rituals.

Subtypes and Dimensions of OCD

Although the DSM-5 presents OCD as a homogeneous condition, research has identified reliable and valid OCD symptom dimensions (Abramowitz et al., 2010; McKay et al., 2004). These include (a) contamination (contamination obsessions and de-contamination rituals), (b) responsibility for harm (aggressive obsessions and checking rituals), (c) incompleteness (obsessions about order or exactness and arranging rituals), and (d) unacceptable “taboo” violent, sexual, or blasphemous thoughts with mental rituals.

Poor Insight

The Diagnostic and Statistical Manual of Mental Disorders (DSM)-5 criteria for OCD include the specifiers “Good or fair insight,” “Poor insight,” and “Absent insight” to denote the degree to which the person views his or her obsessions and rituals as reasonable. Although most people with OCD recognize their symptoms as somewhat senseless, there is a continuum of insight, with 4% of patients convinced that they are realistic (i.e., poor insight; Foa et al., 1995). Poorer insight appears to be associated with religious obsessions, fears of mistakes, and aggressive obsessional impulses (Tolin, Abramowitz, Kozak, & Foa, 2001).

Tic-Related OCD

The DSM-5 also identifies a presentation of OCD in which the individual has a history of tic disorders such as Tourette Syndrome. This putative form of OCD typically involves symmetry and exactness obsessions, and ordering/arranging compulsions.

Interpersonal Aspects of OCD

OCD may have a negative impact on close interpersonal relationships, and the dysfunctional relationship patterns can promote the maintenance of OCD symptoms so that a vicious cycle develops. This can occur in two ways, through accommodation and conflict (Abramowitz et al., 2013).

Symptom Accommodation

Accommodation occurs when a friend or relative participates in their loved one’s rituals, facilitates avoidance, assumes responsibilities for the sufferer, or “helps” to resolve problems that result from obsessions and compulsions. The accommodation might occur at the request (or demand) of the individual with OCD, or on a voluntarily basis by a relative who does not wish to see the sufferer become highly anxious (Boeding et al., 2013). Table 3 shows examples of accommodation behaviors observed in work with couples in which one partner has OCD.

Table 3. Examples of Family Accommodation Behaviors in OCD

OCD Symptom

Partner accommodation behaviors

Contamination and washing symptoms

  • Washing or cleaning for the patient

  • Doing extra laundry

  • Avoiding contaminated stimuli

Obsessional doubting and compulsive checking

  • Assisting with checking rituals

  • Providing reassurance

  • Helping the patient avoid ambiguous situations that might trigger doubts

Violent, sexual, and religious obsessions

  • Providing reassurance

  • Helping with avoidance of stimuli that trigger obsessional thoughts

  • Helping with praying or interpreting Bible passages or religious doubts

Ordering and symmetry (“not just right”) obsessions and compulsions

  • Checking to make sure things are “in order” or arranged properly

  • Repeating answers until they are “just right”

Since avoidance and compulsive rituals prevent the natural reduction of obsessional fear, accommodation to these symptoms by a relative or friend perpetuates OCD symptoms. For instance, consider a man with obsessional fears of acting on unwanted impulses to molest his newborn. By accommodating her husband’s avoidance of changing or bathing the infant child by doing this herself, she prevents him from learning that his anxiety over the senseless obsessions will subside, and that he is unlikely to act on his obsessional thoughts. Indeed, family accommodation predicts more severe OCD symptoms (Van Noppen & Steketee, 2003).

Relationship Conflict

Interdependency, unassertiveness, and avoidant communication patterns that foster stress and conflict are often present in couples and families in which one member has OCD. OCD symptoms and relationship distress influence each other, rather than one exclusively leading to the other. For example, a father’s contentious relationship with his son might contribute to anxiety that develops into obsessional thinking. The son’s excessive ritualistic behaviors might also lead to frequent family arguments. Criticism, hostility, and emotional over-involvement are associated with poorer family functioning in those affected by OCD (Chambless & Steketee, 1999).

Associated Features of OCD


The lifetime prevalence of OCD range is between 0.7% and 2.9% (Kessler et al., 2005; Ruscio, Stein, Chiu, & Kessler, 2010), and there is a slight preponderance of females (Mowrer, 1939). The disorder typically begins by age 25, although onset in childhood or adolescence is common. Mean onset age is earlier in males (about 21 years) than in females (22 to 24 years).


OCD is chronic with a low rate of spontaneous remission. Symptoms fluctuate and worsen with increased life stress. Although full recovery is rare, more individuals receive effective treatments than ever before, leading to improved symptom management.

Cultural and Religious Factors

Research and clinical observations show that factors such as one’s religious and cultural beliefs can influence the presentation of OCD (e.g., Rachman, 1998). For example, obsessions and compulsions related to the fear of violating one’s religious customs are more prevalent in devout individuals and societies than among people and cultures that place less emphasis on religion. The content of common obsessions has also been observed to shift over time within a given society. For example, in the United States, obsessions about contamination from gonorrhea that were prevalent during the 1970s were largely replaced by fears of contamination from HIV/AIDS in the 1980s and 1990s.

Psychological Models

Learning Models

Behavioral models of OCD (Mowrer, 1939) propose that obsessional fears develop via classical conditioning, wherein a previously neutral stimulus is paired with an aversive one. As a result, situations (e.g., using the bathroom), objects (e.g., door handles), and thoughts (e.g., of harm) that pose no objective threat come to evoke obsessional fear. Compulsive rituals and avoidance behaviors then develop as a means of reducing fear yet are negatively reinforced by the immediate (albeit temporary) reduction in distress they engender. Avoidance and escape behaviors, however, prevent the natural extinction of obsessional fears, and thereby maintain such fear.

Cognitive Deficit (Neuropsychological) Models

Some theorists have proposed that OCD symptoms arise from abnormally functioning cognitive processes. Compulsive checking, for example, could develop as a consequence of not being able to remember whether or not one has locked the door, etc. Research, however, has found no consistent evidence of a memory deficit in OCD (e.g., Woods, Vevea, Chambless, & Bayen, 2002). Researchers have hypothesized that compulsive checkers suffer from impairment in explicit memory (e.g., Sher, Frost, & Otto, 1983), low confidence in explicit memory (McNally & Kohlbeck, 1993), or both. In fact, patients appear to have a selectively better memory for OCD-related information relative to non-OCD-relevant stimuli (Radomsky, Rachman, & Hammond, 2001).

The intrusive and repetitious quality of obsessions and compulsions has led some researchers to hypothesize that OCD is characterized by deficits in cognitive and behavioral inhibition— the ability to stop behaviors or dismiss extraneous mental stimuli. Studies examining behavioral impulsivity, and cognitive recall and recognition suggest that people with OCD have more difficulty forgetting negative material, and material related to their obsessional fears, relative to other sorts of material.

There are a number of limitations of cognitive deficit models of OCD. First, they do not account for the heterogeneity of OCD symptoms (e.g., why do some people have washing compulsions while others have checking rituals?). Second, they do not account for the fact that similar mild cognitive deficits have been found in many psychological disorders. Thus, if cognitive deficits play causal role in OCD, it is most likely to be a nonspecific vulnerability factor, as opposed to a specific cause. Third, the differences observed in studies comparing individuals with OCD to those without are generally statistically small, and not clinically meaningful (Abramovitch, Abramowitz, & Mittelman, 2013).

Cognitive-Behavioral Models

The most promising psychological model of OCD is the cognitive-behavioral approach, which is based on the cognitive theory of emotion (Beck, 1976; Beck & Beck, 2011), that psychological disturbance is brought about not by situations and stimuli themselves, but by how one makes sense out of such situations or stimuli. Accordingly, obsessions and compulsions are thought to arise from dysfunctional beliefs, with the strength of these beliefs influencing the person’s degree of insight into his or her OCD symptoms.

This approach begins with the finding that unwanted intrusive thoughts are a normal experience (e.g., Rachman & de Silva, 1978); yet they escalate into clinical obsessions when they are appraised as significant and harmful based on dysfunctional beliefs about the importance of thoughts, the need for certainty, and/or an inflated sense of responsibility for causing and preventing harm. To illustrate, consider an intrusive thought to harm a loved one. Most people experiencing such an intrusion would regard it as a meaningless idea. Yet if the person appraises this thought as significant or meaningful (“I am a terrible and dangerous person”) it will provoke distress and attempts to suppress or remove the unwanted intrusion (e.g., by replacing it with a “good” thought), or to prevent any harmful events associated with it (e.g., avoidance, compulsive reassurance-seeking).

According to this approach, compulsive rituals and avoidance represent efforts to remove intrusions and prevent feared consequences. Salkovskis (1996) advanced two reasons that compulsions and avoidance become persistent and excessive. First, they are negatively reinforced by their ability to reduce distress (as in the learning model). Second, they prevent the person from learning that their appraisals of intrusions are exaggerated and unrealistic. That is, performing the ritual robs the person of the opportunity to discover that the anticipated negative outcome would not have occurred in the first place. If the individual avoids obsessional triggers, there is no opportunity to learn that distressing obsessional thoughts do not pose danger.

The cognitive-behavioral model has strong empirical support (Abramowitz, 2006; Clark, 2004). Research indicates three primary domains of dysfunctional beliefs (shown in Table 4) associated with OCD symptoms (e.g., Wheaton, Abramowitz, Berman, Riemann, & Hale, 2010), and laboratory experiments have demonstrated that inducing such beliefs influences dysfunctional appraisals and exacerbates obsessional symptoms (Rassin, Merckelbach, Muris, & Spaan, 1999). Longitudinal prospective research has also found that these types of beliefs confer vulnerability to the onset or worsening of obsessive-compulsive symptoms under certain conditions (e.g., Abramowitz, Khandker, Nelson, Deacon, & Rygwall, 2006).

Table 4. Domains of Dysfunctional Beliefs in OCD



Inflated responsibility/Overestimation of threat

  • Belief that one has the power to cause and/or the duty to prevent negative outcomes

  • Belief that negative events are likely and would be unmanageable

Exaggeration of the importance of thoughts and need to control thoughts

  • Belief that the mere presence of a thought indicates that the thought is significant.

  • Belief that complete control over one’s thoughts is both necessary and possible

Perfectionism/Intolerance for uncertainty

  • Belief that mistakes and imperfection are intolerable

  • Belief that it is necessary and possible to be 100% certain that negative outcomes will not occur

The cognitive-behavioral approach suggests that successful treatment for OCD must (a) correct dysfunctional beliefs and appraisals that lead to obsessional fear, and (b) terminate avoidance and compulsive rituals that prevent the correction of dysfunctional beliefs and the extinction of anxiety. In short, the task of cognitive-behavior therapy (CBT) is to foster an evaluation of obsessional stimuli as non-threatening and therefore not demanding of further action. Patients must come to understand their problem not in terms of the risk of feared consequences, but in terms of how they are thinking and behaving in response to stimuli that objectively pose a low risk of harm.

Neurobiological Models of OCD

Serotonin Hypothesis

The serotonin hypothesis proposes that OCD is caused by abnormalities in this neurotransmitter system (Zohar, Kennedy, Hollander, & Koran, 2004). The most consistent findings supporting this model come from the pharmacotherapy literature, which suggests that selective serotonin reuptake inhibitor medications (SSRIs; e.g., fluoxetine) are more effective than medications with other mechanisms of action (e.g., imipramine) in reducing OCD symptoms. In contrast, studies of biological markers— such as blood and cerebrospinal fluid levels of serotonin metabolites—have provided inconclusive results regarding a relationship between serotonin and OCD (Insel, Mueller, Alterman, Linnoila, & Murphy, 1985). Similarly, results from studies using the pharmacological challenge paradigm are largely incompatible with the serotonin hypothesis (Hollander et al., 1992).

Neurophysiological Models

These models posit that OCD is caused by anatomical and functional abnormalities in particular areas of the brain, such as the orbitofrontal-subcortical circuits, which are thought to connect brain regions involved in processing information with those involved in the initiation of behavioral responses. These models are derived from neuroimaging studies in which activity levels in specific brain areas are compared between people with and without OCD. Investigations using positron emission tomography (PET) have found increased glucose utilization in the orbitofrontal cortex (OFC), caudate, thalamus, prefrontal cortex, and anterior cingulate among patients with OCD as compared to non-patients (e.g., Baxter et al., 1992). Studies using single photon emission computed tomography (SPECT) have reported decreased blood flow to the OFC, caudate, various areas of the cortex, and thalamus in OCD patients as compared to non-patients (for a review see Whiteside, Port, & Abramowitz, 2004). Finally, studies comparing individuals with OCD to healthy controls using magnetic resonance spectroscopy (MRS) have reported decreased levels of various markers of neuronal viability in the left and right striatum, and in the medial thalamus (e.g., Fitzgerald, Moore, Paulson, Stewart, & Rosenberg, 2000). Although findings vary across studies, a meta-analysis of ten PET and SPECT studies found that relative to healthy individuals, those with OCD evince more activity in the orbital gyrus and the head of the caudate nucleus (Whiteside, Port, & Abramowitz, 2004).

Limitations of Biological Models

Biological models suffer from a number of difficulties. One limitation is that there are no explanations of how neurotransmitter or neuroanatomical abnormalities translate into OCD symptoms as opposed to other psychological disorders. In addition, biological models are unable to explain why (a) OCD symptoms are generally constrained to particular themes, and (b) some people experience one type of obsession (e.g., contamination), but not another (e.g., sexual). Moreover, since the serotonin hypothesis originated from the findings of preferential efficacy of SSRIs over non-serotonergic antidepressants, the assertion that the effectiveness of SSRIs supports the serotonin hypothesis is circular. Further still, there is a logical fallacy in deriving etiological models from treatment results. A final problem is that neurophysiological models are based on correlational studies, which address neither the presence of abnormalities nor whether brain-symptom associations are causal.


Diagnostic Interviews

The Structured Clinical Interview for DSM-5 (SCID-5; First, Williams, Karg, & Spitzer, 2015), the Mini International Neuropsychiatric Interview (MINI; Sheehan et al., 1998), and the Anxiety Disorders Interview Schedule for DSM (ADIS-5; Brown & Barlow, 2014) all assess the cardinal features of OCD. The ADIS provides the most detail about OCD symptoms and assesses severity using dimensional rating scales.

Clinician-Rated Severity Scales

Yale-Brown Obsessive Compulsive Scale

The Yale-Brown Obsessive Compulsive Scale (YBOCS; Goodman, Price, Rasmussen, Mazure, Delgado, et al., 1989; Goodman, Price, Rasmussen, Mazure, Fleischmann, et al., 1989) contains three parts: First, the interviewer provides definitions of obsessions and compulsions. Second, using a symptom checklist of over 50 common obsessions and compulsions, the interviewer asks the patient to indicate whether each symptom is currently present, absent, or present only in the past. The clinician and patient then generate a list of the three most severe obsessions and compulsions. The third section is a 10-item severity scale that assesses (a) the time spent, (b) interference from, (c) distress associated with, (d) efforts to resist, and (e) ability to control obsessions (items 1–5) and compulsions (items 6–10). Each parameter is rated on a scale from 0 (no symptoms) to 4 (extremely severe), and scores on the 10 items are summed to produce a total score ranging from 0 to 40. In most instances, scores of 0 to 7 represent subclinical OCD symptoms, those from 8 to 15 represent mild symptoms, scores of 16 to 23 relate to moderate symptoms, scores from 24 to 31 suggest severe symptoms, and scores of 32 to 40 imply extreme symptoms.

The Y-BOCS is sensitive to multiple aspects of OCD severity independent of the number or types of different obsessions and compulsions. A limitation, however, is that the symptom checklist contains some items that are not genuine obsessions or compulsions (e.g., hair-pulling). Research indicates that the Y-BOCS possesses adequate reliability, validity, and sensitivity to treatment (Taylor, 1995). Conelea, Freeman, and Garcia (2012) have described ways to use the Y-BOCS that are consistent with recent conceptualizations of the links between obsessions and compulsions.

Brown Assessment of Beliefs Scale

The Brown Assessment of Beliefs Scale (BABS; Eisen et al., 1998) is a seven-item interview assessing degree of insight into the senselessness of OCD symptoms. The individual’s main obsessional fear (e.g., “If I touch the floor, I will get sick”) is rated along the following parameters: (a) conviction that the belief is accurate; (b) perception of others’ views about accuracy; (c) explanation for any difference between the patient’s and others’ views of the accuracy of belief; (d) whether the person could be convinced that the belief is wrong; (e) patent’s own attempts to disprove the belief; (f) recognition that the belief has a psychological cause; and (g) an optional item assessing delusions of reference. Each item is rated from 0 to 4, with higher scores indicating poorer insight; the first six items are summed to create a total score (range, 0 to 24; the seventh item is not included in the total score). The BABS has strong internal consistency (α‎ = .87), strong inter-rater and test-retest reliability, and good convergent and discriminant validity.

Self-Report Measures

Numerous self-report and interview measures have been developed to assess OCD symptoms, including the Obsessive Compulsive Inventory and its revision (OCI-R; Foa et al., 2002), the Padua Inventory (Sanavio, 1988) and its revision (Burns, Keortge, Formea, & Sternberger, 1996), and the Vancouver Obsessive Compulsive Inventory (Thordarson et al., 2004). These instruments generally contain items assessing specific and quintessential types of obsessions and compulsions (e.g., “I feel that there are good and bad numbers;” Foa et al., 2002). The items are rated on a scale of agreement, personal relevance, or associated distress.

Abramowitz et al. (2010) developed the Dimensional Obsessive-Compulsive Scale (DOCS) to provide a more global measure of the four most consistently replicated OCD symptom dimensions (which correspond to four DOCS subscales): (a) contamination, (b) responsibility for harm and mistakes, (c) symmetry/ordering, and (d) unacceptable thoughts. Accordingly, the DOCS contains four 5-item subscales. Each subscale begins with a description of the symptom dimension along with examples of representative obsessions and rituals, and then assess the following parameters of severity: (a) time occupied by obsessions and rituals, (b) avoidance behavior, (c) associated distress, (d) functional interference, and (e) difficulty disregarding the obsessions and refraining from the compulsions. The DOCS subscales have excellent reliability in clinical samples (α‎ = .94 – .96), and the measure converges well with other measures of OC symptoms (Abramowitz et al., 2010).

Functional Assessment

Functional assessment is the compiling of patient-specific information about the antecedents and consequences of target behaviors and emotions. Cognitive-behavioral theory dictates what information is collected and how it is organized to form a conceptualization of the problem that drives treatment planning.

Obsessional Triggers

Stimuli that evoke obsessional fear include external cues such as objects and situations (e.g., public bathrooms, knives, numbers, leaving the house), which might be assessed by asking questions such as, “what situations make you anxious?” “what do you avoid?” and “what triggers you to want to do rituals?” It is also important to assess the particular distressing thoughts, ideas, images, and doubts (i.e., obsessional thoughts) that provoke fear. Questions to elicit this information include, “what intrusive thoughts do you have that trigger anxiety?” and “what thoughts do you try to avoid, resist, or dismiss?”

Feared Consequences

It is also essential to assess the cognitive basis of the individual’s fear. For example, what does the person worry will happen if they are exposed to obsessional stimuli? Examples of questions to elicit feared consequences include, “what is the worst thing that might happen if you touch someone’s shoe?” and “if you don’t pray, what are you afraid will happen?” The assessor should also assess mistaken beliefs about the presence and meaning of intrusive thoughts; for example, “what do you think it means that you have these sexual thoughts?” Some individuals also fear anxiety-related bodily sensations, such as a racing heart, hot flash, muscle tension (e.g., in the groin during unwanted sexual thoughts), and racing thoughts. Thus, functional assessment should include an inquiry of such somatic stimuli.

The Obsessive Beliefs Questionnaire (OBQ) and Interpretation of Intrusions Inventory (III) are self-report instruments developed to measure a range of OCD-related cognitive distortions (Frost & Steketee, 2002). These psychometrically strong measures are useful to include in the functional assessment to augment interview data.

Avoidance and Rituals

Assessment of behaviors performed to control or reduce fear—such as avoidance and compulsive rituals—is a critical part of the functional analysis. Most individuals with OCD avoid obsessional stimuli such as certain people (e.g., the homeless), places (e.g., gas stations), situations (e.g., using public bathrooms), and words (e.g., “devil”).

In addition to gathering detailed information about all avoidance and overt compulsive behavior, covert rituals such as wiping, using special soaps, and brief checks should also be assessed. In addition, it is important to ascertain any mental rituals and other cognitive strategies the patient uses in response to obsessional stimuli. Examples include thinking “good” thoughts in response to a “bad” thought, repeating phrases or prayers, mental reviewing or checking, and thought suppression or cognitive distraction. Finally, it is important to assess the cognitive links between avoidance/rituals and obsessional thoughts. For example, “I need to check that all the lights are off in order to prevent causing a fire.”


Self-monitoring is used to augment functional assessment, wherein the patient completes a log sheet on which he or she records (a) date, (b) time, (c) obsessional thought or stimulus that triggers anxiety, (d) level of anxiety on a scale of 0 to 10, and (e) the ritual or avoidance behavior employed. Such monitoring helps the clinician and patient gain a complete picture of symptom severity and the relationship between obsessions and compulsions. It can also help the patient identify symptoms he or she might not be aware of.

Psychological Treatment

Cognitive-behavior therapy (CBT), a set of techniques derived from the cognitive-behavioral theoretical model described earlier, is the most effective psychological treatment of OCD. The specific CBT methods that have been examined in the most clinical studies, and that have the most efficacy are exposure and response prevention (ERP), which are typically used in tandem. Detailed guidelines for planning and implementing ERP are provided in various treatment manuals (e.g., Abramowitz & Jacoby, 2014a).

Exposure entails repeated practice confronting stimuli that provoke obsessional fear, but that objectively pose low risk of harm. Exposure can occur in the form of repeated actual encounters with the feared situations and stimuli (situational exposure), and in the form of imaginal confrontation (imaginal exposure) to the feared negative consequences of confronting these situations. For example, an individual with obsessional fears of becoming a murderer if she watches horror movies might practice watching such movies for situational exposure and also practice imaginal exposure to the possibility that this will turn her into a violent person. A patient with fears of becoming ill from contamination by “floor germs” might touch floors and shoes for situational exposure and then confront thoughts of coming down with a serious illness as a result of his exposure to these “contaminants.”

Despite the fear that is provoked during exposure, patients are encouraged to engage in the tasks completely, and without performing obvert or subtle rituals (i.e., response prevention). Over time, the anxiety (and associated physiological responding) usually subsides naturally—a process called habituation. With each repetition of the exposure task, habituation may occur more rapidly. Response prevention helps to prolong exposure and facilitate the eventual extinction of obsessional anxiety. In the examples above, the first patient might practice refraining from any strategies she typically uses to reassure herself that she will not become murderous, such as mentally telling herself “I’m good, I’m good, I’m good …” The second patient would be instructed to refrain from rituals such as washing or cleaning.

The Delivery of ERP

A course of ERP ordinarily begins with the assessment of obsessions, compulsive rituals, avoidance strategies, and the patient’s feared consequences of confronting feared situations without performing rituals. This information is then used to plan the specific exposure exercises that will be implemented. The term “response prevention” does not imply that the patient is physically restrained from performing rituals. Rather, the therapist helps the patient resist urges to carry out these behaviors. Accordingly, providing a convincing rationale for how ERP is helpful in reducing OCD is also a critical component of the first few treatment sessions. Such a rationale must motivate the patient to tolerate the distress that typically accompanies therapy.

Although the exposure exercises in ERP may be implemented beginning with moderately distressing items and progressing to those most distressing, one does not need to use a hierarchical approach. In fact, there might be benefit to using a random and varied approach to exposure to teach patients learn that they can (a) tolerate uncertainty and (b) manage varying degrees of fear (e.g., Abramowitz & Jacoby, 2015). At the end of each treatment session, the therapist instructs the patient to continue exposure in different environmental contexts, without the therapist present. This helps promote generalization of learning.

Mechanisms of Change

ERP works by providing opportunities for the extinction of conditioned fear responses. Traditionally this process was understood in terms of emotional processing theory (e.g., Foa, Huppert, & Cahill, 2006; Foa & Kozak, 1986), which credits initial fear activation followed by habituation of fear (both within and between sessions) as the mechanisms of improvement. Habituation during exposure, however, is not a strong predictor of long-term outcomes with ERP; and successful outcomes can occur in the absence of habituation (Craske, Treanor, Conway, Zbozinek, & Vervliet, 2014). Rather, research on learning and memory points to inhibitory learning as the mechanism of extinction (e.g., Craske et al., 2014). From this perspective, exposure therapy leaves original danger-based associations between the conditioned and unconditioned stimulus (e.g., “floors cause sickness”) intact, while competing non-danger-based associations (e.g., ‘floors are safe’) are formed. The goal of ERP for OCD, then, is to optimize the likelihood that the non-danger associations will inhibit access to the older threat associations (Abramowitz & Arch, 2014; Jacoby & Abramowitz, 2016).

The Efficacy of ERP

Studies evaluating the effectiveness of ERP consistently show that patients who complete this treatment achieve clinically significant and durable improvement. Average improvement rates are typically from 50% to 70% in these studies (Olatunji, Davis, Powers, & Smits, 2013). A review of 16 trials (involving 756 patients) indicated that ERP was substantially more effective than comparison treatments (e.g., relaxation, anxiety management training, waiting list, medication) immediately following therapy (effect size = 1.39) and moderately more effective at long-term follow-up (effect size = 0.43; Olatunji et al., 2013). These trials indicate that the effects of ERP are due to the specific techniques over and above the factors common to all interventions, such as the therapeutic relationship and spontaneous improvement. Moreover, the effects of ERP are not limited to highly selected research samples or to treatment as delivered in specialty clinics. Effectiveness studies conducted with nonresearch patients (e.g., Franklin, Abramowitz, Kozak, Levitt, & Foa, 2000) show that over 80% of patients who complete ERP achieve clinically significant improvement. While ERP is effective in both the short and long term for most people with OCD, about 20% do not respond, and about 25–30% drop out of therapy.

Biological Treatments

Serotonin Reuptake Inhibitors

Pharmacotherapy using selective serotonin reuptake inhibitor (SSRI) medication is the most widely used treatment for OCD. The specific agents in this class of drugs include fluoxetine, paroxetine, sertraline, citalopram, and fluvoxamine. Clomipramine, a tricyclic medication that also possesses serotonergic properties, is also used in the treatment of OCD. Problems with the serotonin hypothesis (as discussed earlier in this chapter) withstanding, it is this model that provides the rationale for the use of serotonergic medications to treat OCD. On average, serotonin medications produce a 20%–40% reduction in obsessions and compulsions (e.g., Abramowitz, Taylor, & McKay, 2009). The major strengths of a pharmacological approach to treating OCD include the convenience and the requirement of little effort on the patient’s part. Limitations include the relatively modest improvement and likelihood of residual symptoms, high rate of non-response (40%–60% of patients do not show any favorable response), and the prospect of unpleasant side effects (which can often be stabilized by adjusting the dose). Moreover, once SRIs are terminated, OCD symptoms typically return rapidly (Pato, Zohar-Kadouch, Zohar, & Murphy, 1988).


Few syndromes in psychopathology have generated as much curiosity and clinical exploration as OCD. Since the 1970’s, research on OCD has increased exponentially, leading to a clearer understanding of the heterogeneity of the disorder, its boundaries with other syndromes, and the development of increasingly sophisticated theoretical models of etiology and maintenance. Perhaps most importantly, research has led to advances in treatment; and whereas the first line therapies (ERP and serotonergic medication) are not entirely effective for every sufferer, they have transformed OCD from an unmanageable lifetime affliction into a treatable problem that need not reduce quality of life.

Further Reading

Abramowitz, J. S. (1997). Effectiveness of psychological and pharmacological treatments for obsessive-compulsive disorder: A quantitative review. Journal of Consulting and Clinical Psychology, 65(1), 44–52.Find this resource:

Abramowitz, J. S. (2013). The practice of exposure therapy: Relevance of cognitive-behavioral theory and extinction theory. Behavior Therapy, 44(4), 548–558.Find this resource:

Abramowitz, J. S., Wheaton, M. G., & Storch, E. A. (2008). The status of hoarding as a symptom of obsessive-compulsive disorder. Behaviour Research and Therapy, 46(9), 1026–1033.Find this resource:

Foa, E. B., Liebowitz, M. R., Kozak, M. J., Davies, S., Campeas, R., Franklin, M. E., et al. (2005). Randomized, placebo-controlled trial of exposure and ritual prevention, clomipramine, and their combination in the treatment of obsessive-compulsive disorder. The American Journal of Psychiatry, 162(1), 151–161.Find this resource:

Rachman, S. J. (1998). A cognitive theory of obsessions: Elaborations. Behaviour Research and Therapy, 36(4), 385–401.Find this resource:

Rachman, S. J. (2002). A cognitive theory of compulsive checking. Behaviour Research and Therapy, 40(6), 624–639.Find this resource:

Rachman, S. J. (2003). The treatment of obsessions. New York: Oxford University Press.Find this resource:

Rachman, S. J., & de Silva, P. (1978). Abnormal and normal obsessions. Behaviour Research and Therapy, 16(4), 233–248.Find this resource:

Salkovskis, P. M. (1997). Obsessional–compulsive problems: A cognitive–behavioral analysis. In S. J. Rachman (Ed.), Best of behavior research and therapy (pp. 29–41). Amsterdam: Pergamon/Elsevier Science.Find this resource:


Abramovitch, A., Abramowitz, J. S., & Mittelman, A. (2013). The neuropsychology of adult obsessive–compulsive disorder: A meta-analysis. Clinical Psychology Review, 33(8), 1163–1171.Find this resource:

Abramowitz, J. S. (1997). Effectiveness of psychological and pharmacological treatments for obsessive-compulsive disorder: A quantitative review. Journal of Consulting and Clinical Psychology, 65(1), 44–52.Find this resource:

Abramowitz, J. S. (2006). Understanding and treating obsessive-compulsive disorder: A cognitive-behavioral approach. Mahwah, NJ: Lawrence Erlbaum.Find this resource:

Abramowitz, J. S. (2013). The practice of exposure therapy: Relevance of cognitive-behavioral theory and extinction theory. Behavior Therapy, 44(4), 548–558.Find this resource:

Abramowitz, J. S., & Arch, J. J. (2014). Strategies for improving long-term outcomes in cognitive behavioral therapy for obsessive-compulsive disorder: Insights from learning theory. Cognitive and Behavioral Practice, 21, 20–31.Find this resource:

Abramowitz, J. S., Baucom, D. H., Wheaton, M. G., Boeding, S., Fabricant, L. E., Paprocki, C., et al. (2013). Enhancing exposure and response prevention for OCD: A couple-based approach. Behavior Modification, 37(2), 189–210.Find this resource:

Abramowitz, J. S., Deacon, B. J., Olatunji, B. O., Wheaton, M. G., Berman, N. C., Losardo, D., et al. (2010). Assessment of obsessive-compulsive symptom dimensions: Development and evaluation of the Dimensional Obsessive-Compulsive Scale. Psychological Assessment, 22(1), 180–198.Find this resource:

Abramowitz, J. S., Fabricant, L. E., Taylor, S., Deacon, B. J., McKay, D., & Storch, E. A. (2014). The utility of analogue studies for understanding obsessions and compulsions. Clinical Psychology Review, 34(3), 206–217.Find this resource:

Abramowitz, J. S., & Jacoby, R. J. (2014a). Obsessive-compulsive disorder in adults. Boston: Hogrefe.Find this resource:

Abramowitz, J. S., & Jacoby, R. J. (2014b). Obsessive-compulsive disorder in the DSM-5. Clinical Psychology: Science and Practice, 21(3), 221–235.Find this resource:

Abramowitz, J. S., & Jacoby, R. J. (2015). Obsessive-compulsive and related disorders: A critical review of the new diagnostic class. Annual Review of Clinical Psychology, 11, 165–186.Find this resource:

Abramowitz, J. S., Khandker, M., Nelson, C. A., Deacon, B. J., & Rygwall, R. (2006). The role of cognitive factors in the pathogenesis of obsessive-compulsive symptoms: A prospective study. Behaviour Research and Therapy, 44(9), 1361–1374.Find this resource:

Abramowitz, J. S., Taylor, S., & McKay, D. (2009). Obsessive-compulsive disorder. The Lancet, 374(9688), 491–499.Find this resource:

Abramowitz, J. S., Wheaton, M. G., & Storch, E. A. (2008). The status of hoarding as a symptom of obsessive-compulsive disorder. Behaviour Research and Therapy, 46(9), 1026–1033.Find this resource:

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Clark, D. A. (2004). Cognitive-behavioral therapy for OCD. London: Guilford Press.Find this resource:

Conelea, C. A., Freeman, J. B., & Garcia, A. M. (2012). Integrating behavioral theory with OCD assessment using the Y-BOCS/CY-BOCS symptom checklist. Journal of Obsessive-Compulsive and Related Disorders, 1(2), 112–118.Find this resource:

Craske, M. G., Treanor, M., Conway, C. C., Zbozinek, T., & Vervliet, B. (2014). Maximizing exposure therapy: An inhibitory learning approach. Behaviour Research and Therapy, 58, 10–23.Find this resource:

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Foa, E. B., Huppert, J. D., Leiberg, S., Langner, R., Kichic, R., Hajcak, G., et al. (2002). The Obsessive-Compulsive Inventory: Development and validation of a short version. Psychological Assessment, 14(4), 485–496.Find this resource:

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Foa, E. B., Liebowitz, M. R., Kozak, M. J., Davies, S., Campeas, R., Franklin, M. E., et al. (2005). Randomized, placebo-controlled trial of exposure and ritual prevention, clomipramine, and their combination in the treatment of obsessive-compulsive disorder. The American Journal of Psychiatry, 162(1), 151–161.Find this resource:

Franklin, M. E., Abramowitz, J. S., Kozak, M. J., Levitt, J. T., & Foa, E. B. (2000). Effectiveness of exposure and ritual prevention for obsessive-compulsive disorder: Randomized compared with nonrandomized samples. Journal of Consulting and Clinical Psychology, 68(4), 594–602.Find this resource:

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Hollander, E., DeCaria, C. M., Nitescu, A., Gully, R., Suckow, R. F., Cooper, T. B., et al. (1992). Serotonergic function in obsessive-compulsive disorder. Behavioral and neuroendocrine responses to oral m-chlorophenylpiperazine and fenfluramine in patients and healthy volunteers. Archives of General Psychiatry, 49(1), 21–28.Find this resource:

Insel, T. R., Mueller, E. A., Alterman, I., Linnoila, M., & Murphy, D. L. (1985). Obsessive-compulsive disorder and serotonin: Is there a connection?Biological Psychiatry, 20(11), 1174–1188.Find this resource:

Jacoby, R. J., & Abramowitz, J. S. (2016). Inhibitory learning approaches to exposure therapy: A critical review and translation to obsessive-compulsive disorder. Clinical Psychology Review, 49, 28–40.Find this resource:

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McKay, D., Abramowitz, J. S., Calamari, J. E., Kyrios, M., Radomsky, A., Sookman, D., et al. (2004). A critical evaluation of obsessive-compulsive disorder subtypes: Symptoms versus mechanisms. Clinical Psychology Review, 24(3), 283–313.Find this resource:

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Pato, M. T., Zohar-Kadouch, R., Zohar, J., & Murphy, D. L. (1988). Return of symptoms after discontinuation of clomipramine in patients with obsessive-compulsive disorder. The American Journal of Psychiatry, 145(12), 1521–1525.Find this resource:

Rachman, S. J. (1998). A cognitive theory of obsessions: Elaborations. Behaviour Research and Therapy, 36(4), 385–401.Find this resource:

Rachman, S. J. (2002). A cognitive theory of compulsive checking. Behaviour Research and Therapy, 40(6), 624–639.Find this resource:

Rachman, S. J. (2003). The treatment of obsessions. New York: Oxford University Press.Find this resource:

Rachman, S. J., & de Silva, P. (1978). Abnormal and normal obsessions. Behaviour Research and Therapy, 16(4), 233–248.Find this resource:

Radomsky, A. S., Rachman, S., & Hammond, D. (2001). Memory bias, confidence, and responsibility in compulsive checking. Behaviour Research and Therapy, 39(7), 813–822.Find this resource:

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Salkovskis, P. M. (1996). Cognitive-behavioral approaches to the understanding of obsessional problems. In R. M. Rapee (Ed.), Current controversies in the anxiety disorders (pp. 103–133). New York: Guilford Press.Find this resource:

Salkovskis, P. M. (1997). Obsessional–compulsive problems: A cognitive–behavioral analysis. In S. J. Rachman (Ed.), Best of behavior research and therapy (pp. 29–41). Amsterdam: Pergamon/Elsevier Science.Find this resource:

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