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 patients diagnosed with OCD are at a 5-fold increase to develop OCD at some point throughout their lifespan (Nestadt, et al., 2000).

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).

Initial studies exploring genetic factors for BDD and hoarding also indicate a likely hereditary influence; however, environmental factors appear to play a larger role in the development of these disorders than that of OCD (Ahmed, et al., 2014; Lervolino et al., 2009).

Neurotransmitters

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 these patients report a significant reduction in their depressive symptoms, but also significant improvement in their OCD symptoms (Bokor & Anderson, 2014). Interestingly enough, antidepressant medications that do not effect 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 filters 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 over activity of the orbitofrontal cortex and a lack of filtering in the caudate nuclei, thus causing too many impulses 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 harm, control, or uncertainty in their life, thus leading them to over interpret potential negative outcomes of events. 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 to repeat the compulsive behavior multiple times to ensure it is done correctly. These cognitive biases are supported throughout research studies that repeatedly find 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 so often why does this happen? Everyone has times when they have repetitive or intrusive thoughts such as: “Did I shut 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 up on their thoughts once, or even forgo checking their thoughts 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 their 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 related disorders focuses on the explanation of compulsions rather than obsessions. Behaviorists believe that these compulsions are maintained by operant conditioning. As you may remember, operant condition is a type of associative learning based on contingencies (e.g., “If I do X, then Y will happen”). How does this explain compulsions in OCD and related disorders? Well, an individual with OCD may experience negative thoughts or anxiety related to an unpleasant event. These thoughts/anxieties cause significant distress to the individual, and therefore, they seek out some kind of behavior (compulsion) to alleviate these threats. This provides temporary relief to the individual, thus reinforcing the compulsive behaviors used to alleviate the threat. Over time, the compulsive behaviors are negatively reinforced due to the temporary relief of anxiety that the compulsion provides (ie., a “bad” thing being taken away due to the compulsion).

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 patients conditioning associated with the obsessions and compulsions by preventing the individual from engaging in the compulsion.

“Etiology of Obsessive-Compulsive and Related Disorders” is adapted from Abnormal Psychology by Coursehero, used under CC BY-SA: Attribution-ShareAlike.