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5.1 Obsessive-Compulsive Disorder

Section Learning Objectives

  • Describe how obsessive-compulsive disorder presents itself.
  • Describe the epidemiology of obsessive-compulsive disorder.
  • Indicate which disorders are commonly comorbid with obsessive-compulsive disorder.
  • Describe the biological, cognitive, and behavioral theories for the etiology of obsessive-compulsive disorder.
  • Describe the treatment options for obsessive-compulsive disorder.

5.1.1 Clinical Description

Obsessive-compulsive disorder, more commonly known as OCD, requires the presence of obsessions and/or compulsions. Obsessions are defined as repetitive and intrusive thoughts, urges, or images. These obsessions are persistent, time-consuming, and unwanted, often causing significant distress and impairment in an individual’s daily functioning. Common obsessions are contamination (dirt on self or objects), errors of uncertainty regarding daily behaviors (locking a door, turning off appliances), thoughts of physical harm or violence, and orderliness, to name a few (Cisler, Adams, et. al., 2011; Yadin & Foa, 2009). Often the individual will try to ignore these thoughts, urges, or images. When they are unable to ignore them, the individual will engage in compulsatory behaviors to alleviate the anxiety.

Compulsions are defined as repetitive behaviors or mental acts that an individual typically performs in response to an obsession. Common examples of compulsions are checking (i.e. repeatedly checking if the stove is turned off even though the first four times they checked it was off), counting (i.e. flicking the lights off and on 5 times), hand washing, organizing objects in a symmetrical manner, and repeating specific words. These compulsive behaviors are typically performed in an attempt to alleviate the anxiety associated with the obsessive thoughts. For example, an individual may feel as though his hands are dirty after using utensils at a restaurant. He may obsess over this thought for a period of time, impacting his ability to interact with others or complete a specific task. This obsession will ultimately lead to the individual performing a compulsion where he will wash his hands with extremely hot water to rid all the germs, or even wash his hands a specified number of times if he also has a counting compulsion. At this point, the individual’s anxiety may be temporarily relieved.

These obsessions and compulsions are more excessive than the typical “cleanliness” as they consume a large part of the individual’s day. Indeed, in order to be considered clinical OCD, the obsessions or compulsions must consume more than 1 hour per day, cause distress, or result in impairment in functioning. Given the example above, an individual with a fear of contamination may refuse to eat out at restaurants or may bring his own utensils with him and insist on using them when he is not eating at home.

5.1.2 Epidemiology

The one-year prevalence rate for OCD is approximately 1.2% both in the US, and worldwide (APA, 2013). OCD has a balanced sex ratio in adults; however, in childhood, boys are diagnosed more frequently than girls (APA, 2013). With respect to gender and symptoms, females are more likely to be diagnosed with cleaning-related obsessions and compulsions, whereas males are more likely to display symptoms related to forbidden thoughts and symmetry (APA, 2013). Additionally, males have an earlier age of onset (5-15 yrs) compared to women (20-24 yrs; Rasmussen & Eisen, 1990). Approximately two-thirds of all individuals with OCD had some symptoms present before the age of 15 (Rasmussen & Eisen, 1990). Overall the average age of onset of OCD iis 19.5 years.

5.1.3 Comorbidity

There is a high comorbidity rate between OCD and other anxiety disorders. Nearly 76% of individuals with OCD will be diagnosed with another anxiety disorder, most commonly panic disorder, social anxiety disorder, generalized anxiety disorder, or a specific phobia (APA, 2013). Additionally, 63% of those with OCD will also be diagnosed with a mood disorder (APA, 2013).

There is a high comorbidity rate between OCD and tic disorder, particularly in males with an onset of OCD in childhood. Children presenting with early-onset OCD typically have a different presentation of symptoms than traditional OCD. Research has also indicated a strong triad of OCD, Tic disorder, and attention-deficit/hyperactivity disorder in children. Due to this triad of psychological disorders, it is believed there is a neurobiological mechanism at fault for the development and maintenance of the disorders.

It should be noted that there are several disorders- schizophrenia, bipolar disorder, eating disorders, and Tourettes – where there is a higher incidence of OCD than the general public (APA, 2013). Therefore, clinicians who have a client diagnosed with one of the disorders above, should also routinely assess him/her for OCD.

5.1.4 Etiology Biological

There are a few biological explanations for obsessive-compulsive related disorders including: hereditary transmission, neurotransmitter deficits, and abnormal functioning in brain structures.

Hereditary Transmission

With regards to heritability studies, twin studies routinely support the role of genetics in the development of obsessive-compulsive behaviors, as monozygotic twins have a substantially greater concordance rate (80-87%) than dizygotic twins (47-50%; Carey & Gottesman, 1981; van Grootheest, Cath, Beekman, & Boomsma, 2005). Additionally, first degree relatives of individuals diagnosed with OCD are twice as likely to develop OCD (APA, 2013).

In general, first-degree biological relatives of people with OCD have a 2-fold increased risk of developing OCD (Pauls, 2010). Interestingly, a study conducted by Nestadt and colleagues (2000) exploring the familial role in the development of obsessive-compulsive disorder found that family members of individuals with OCD had higher rates of both obsessions and compulsions than control families; however, obsessions were more specific to the family members than that of the disorder. This suggests that there is a stronger heritability association for obsessions than compulsions. This study also found a relationship between age of onset of OCD symptoms and family heritability. Individuals who experienced an earlier age of onset, particularly before age 17, were found to have more first-degree relatives diagnosed with OCD. In fact, after the age of 17, there was no relationship between family diagnoses, suggesting those who develop OCD at an older age may have a different diagnostic origin (Nestadt, et al., 2000).


Neurotransmitters, particularly serotonin have been identified as a contributing factor to obsessive and compulsive behaviors. This discovery was actually on accident. When individuals with depression and comorbid OCD were given antidepressant medications clomipramine and/or fluoxetine (both of which increase levels of serotonin) to mediate symptoms of depression, not only did they report a significant reduction in their depressive symptoms, but they also experienced significant improvement in their symptoms of OCD (Bokor & Anderson, 2014). Interestingly enough, antidepressant medications that do not affect serotonin levels are not effective in managing obsessive and compulsive symptoms, thus offering additional support for deficits of serotonin levels as an explanation of obsessive and compulsive behaviors (Sinopoli, Burton, Kronenberg, & Arnold, 2017; Bokor & Anderson, 2014). More recently, there has been some research implicating the involvement of additional neurotransmitters – glutamate, GABA, and dopamine – in the development and maintenance of OCD, although future studies are still needed to draw definitive conclusions (Marinova, Chuang, & Fineberg, 2017).

Brain Structures

Seeing as neurotransmitters have a direct involvement in the development of obsessive-compulsive behaviors, it’s only logical that brain structures that house these neurotransmitters also likely play a role in symptom development. Neuroimaging studies implicate the brain structures and circuits in the frontal lobe, more specifically, the orbitofrontal cortex, which is located just above each eye (Marsh et al., 2014). This brain region is responsible for mediating strong emotional responses and converts them into behavioral responses. Once the orbitofrontal cortex receives sensory/emotional information via sensory inputs, it transmits this information through impulses. These impulses are then passed on to the caudate nuclei which filter through the many impulses received, passing along only the strongest impulses to the thalamus. Once the impulses reach the thalamus, the individual essentially reassesses the emotional response and decides whether or not to act behaviorally (Beucke et al., 2013). It is believed that individuals with obsessive-compulsive behaviors experience overactivity of the orbitofrontal cortex and a lack of filtering in the caudate nuclei, thus causing too many impulses to be transferred to the thalamus (Endrass et al., 2011). Further support for this theory has been shown when individuals with OCD experience brain damage to the orbitofrontal cortex or caudate nuclei and experience remission of OCD symptoms (Hofer et al., 2013). Cognitive

Cognitive theorists believe that OCD behaviors occur due to an individual’s distorted thinking and negative cognitive biases. More specifically, individuals with OCD are more likely to overestimate the probability of threat and harm, to have an inflated sense of responsibility for preventing harm, to think thoughts are important and need to be controlled, and to be perfectionistic. Additionally, some research has indicated that those with OCD also experience disconfirmatory bias, which causes the individual to seek out evidence that proves they failed to perform the ritual or compensatory behavior incorrectly (Sue, Sue, Sue, & Sue, 2017). Finally, individuals with OCD often report the inability to trust themselves and their instincts, and therefore, feel the need to repeat the compulsive behavior multiple times to ensure it is done correctly. These cognitive biases are supported throughout research studies that repeatedly find that individuals with OCD experience more intrusive thoughts than those without OCD (Jacob, Larson, & Storch, 2014).

Now that we have identified that individuals with OCD experience cognitive biases and that these biases contribute to the obsessive and compulsive behaviors, we have yet to identify why these cognitive biases occur. Everyone has times when they have repetitive or intrusive thoughts such as: “Did I turn the oven off after cooking dinner?” or “Did I remember to lock the door before I left home?” Fortunately, most individuals are able to either check once or even forgo checking after they confidently talk themselves through their actions, ensuring that the behavior in question was or was not completed. Unfortunately, individuals with OCD are unable to neutralize these thoughts without performing a ritual as a way to put themselves at ease. As you will see in more detail in the behavioral section below, the behaviors (compulsions) used to neutralize the thoughts (obsessions) provide a temporary relief to the individual. As the individual is continually exposed to the obsession and repeatedly engages in the compulsive behaviors to neutralize the anxiety, the behavior is repeatedly reinforced, thus becoming a compulsion. This theory is supported by studies where individuals with OCD report using more neutralizing strategies and report significant reductions in anxiety after employing these neutralizing techniques (Jacob, Larson, & Storch, 2014; Salkovskis, et al., 2003). Behavioral

The behavioral explanation of obsessive-compulsive disorder focuses on the explanation of compulsions rather than obsessions. Behaviorists believe that these compulsions begin with and are maintained by the classical conditioning. As you may remember, classical conditioning occurs when an unconditioned stimulus is paired with a conditioned stimulus to produce a conditioned response. How does this help explain OCD? Well, an individual with OCD may experience negative thoughts or anxieties related to an unpleasant event (obsession; unconditioned stimulus). These thoughts/anxieties cause significant distress to the individual, and therefore, they seek out some kind of behavior (compulsion) to alleviate these threats (conditioned stimulus). This provides temporary relief to the individual, thus reinforcing the compulsive behaviors used to alleviate the threat. Over time, the conditioned stimulus (compulsive behaviors) are reinforced due to the repeated exposure of the obsession and the temporary relief that comes with engaging in these compulsive behaviors.

Strong support for this theory is the fact that the behavioral treatment option for OCD – exposure and response prevention – is among the most effective treatments for these disorders. As you will read below, this treatment essentially breaks the classical conditioning associated with the obsessions and compulsions through extinction (by preventing the individual from engaging in the compulsive behavior until anxiety is reduced).

5.1.5 Treatment Exposure and Response Prevention 

Treatment of OCD has come a long way in recent years. Among the most effective treatment options is exposure and response prevention (March, Frances, Kahn, & Carpenter, 1997). First developed by psychiatrist Victor Meyer (1966), individuals are repeatedly exposed to their obsession, thus causing anxiety/fears, while simultaneously being prevented from engaging in their compulsive behaviors. Exposure sessions are often done in vivo, or in real life, via videos, or even imaginary, depending on the type of obsession.

Prior to beginning the exposure and response prevention exercises, the clinician must teach the client relaxation techniques for them to engage to cope with the distress of being exposed to the obsession. Once relaxation techniques are taught, the clinician and client will develop a hierarchy of obsessions. Treatment will start at those with the lowest amount of distress to ensure the client has success with treatment and to reduce the likelihood the client will withdrawal from treatment.

Within the hierarchy of obsessions, the individual is gradually exposed to their obsession. For example, an individual obsessed with germs might first watch a person sneeze on the computer in session. Once anxiety is managed and compulsions are resisted at this level of exposure, the individual would move on to being present in the same room as a sick individual, to eventually shaking hands with someone obviously sick, each time helping the client resist the compulsion to engage in the compulsive behavior. Once this level of the hierarchy is managed, they would move on to the next obsession and so forth until the entire list is complete.

Exposure and response prevention is very effective in treating individuals with OCD. In fact, some studies suggest up to an 86% response rate when treatment is completed (Foa et al., 2005). The largest barrier to treatment with OCD is getting clients to commit to treatment, as the repeated exposures and prevention of compulsive behaviors can be quite distressing to clients. Psychopharmacology

There has been minimal support for the treatment of OCD with medication alone. This is likely due to the temporary resolution of symptoms during medication use. Among the most effective medications are those that inhibit the reuptake of serotonin (e.g., clomipramine or SSRI’s). Reportedly, up to 60% of people do show improvement in symptoms while taking these medications; however, symptoms are quick to return when medications are discontinued (Dougherty, Rauch, & Jenike, 2002). While there has been some promise in a combined treatment option of exposure and response prevention and SSRIs, these findings were not superior to exposure and response prevention alone, suggesting that the inclusion of medication in treatment does not provide any added benefit (Foa et al., 2005).


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