Neuroscience of Obsessive-Compulsive Disorder

Obsessive-compulsive disorder is an extremely complex topic. To tackle this, we’ll need to break it down. This first post will be a brief overview of the disorder as it is diagnosed and as it is seen in the brain. Later, we will get to the specific affective and cognitive highlights, and if you’re still with me, we can talk treatment options and how effective they really are.

Diagnosing OCD

According to the American Psychiatric Association, OCD must have the presence of obsessions, “recurrent and persistent thoughts, urges, or images…intrusive and unwanted…”(p. 237), compulsions, “repetitive behaviors…or mental acts…aimed at preventing or reducing anxiety or stress, or preventing some dreaded event…” (p. 237), or both (DSM, 2013). These obsessions and compulsions must be time-consuming or cause distress, and cannot be attributed to substances or another medical or mental condition in order for OCD to be diagnosed (DSM, 2013).

Obsessions and Compulsions

The obsessions of OCD individuals have been found to involve thoughts or fears surrounding contamination, symmetry and exactness, hoarding, and sexual or religious obsessions (Leckman et al, 1997). Compulsions are usually categorized in various dimensions including cleaning, ordering and arranging, checking, hoarding, and rituals (Leckman et al, 1997). Compulsive checking, such as checking locks, switches, or the safety of others, has been found to be strongly correlated with an OCD diagnosis (Stasik, Naragon-Gainey, Chmielewski, & Watson, 2012). A study by Stasik et al showed that both compulsive cleaning and compulsive rituals, such as counting or tapping in certain patterns, also correlate with OCD diagnosis (Stasik, 2012). However, hoarding symptoms may not be specific to OCD, and have been found to correlate with other disorders (Stasik, 2012).

What drives these compulsive behaviors?

One study by Steketee, Frost and Cohen (1998) found evidence that OCD patients, on average and compared to a nonclinical population, hold different beliefs about responsibility, control, threat estimation, tolerance of uncertainty, concern about anxiety or discomfort, and coping. Thoughts dealing with perfectionism and “just not right” experiences have also been associated with OCD symptoms (Summers, Fitch, & Cougle, 2014). These affective and cognitive variations and others will be discussed more in posts to come.

Inside the brain…

The main brain regions that are associated with OCD include the ventral striatum and orbitofrontal cortex (OFC), as well as the anterior cingulate cortex (ACC) (Tukel, Aydin, Ertekin, Ozyildirim, & Taravari, 2014; Harrison et al, 2013). Studies have suggested a dysfunction in the cortico-striatal-thalamo-cortical (CSTC) circuit is a key feature of OCD (Tukel, 2014). This circuit runs from the OFC to the striatum, to the thalamus, and back to the OFC. Supporting this theory, a study by Harrison et al (2014) showed evidence that changes in pathways among the OFC and striatal regions may be common to all forms of OCD, and the level of hyperactivity there may correlate to the severity of the OCD. They also found evidence that differing symptom types may relate to distinct functional connectivity (Harrison et al, 2014). Their results showed that symptoms of aggression obsessions corresponded with change in connectivity between ventral striatum, amygdala, and the ventromedial frontal cortex, while symptoms of sexual/religious symptoms corresponded with ventral striatal and insular connectivity (Harrison et al, 2014).

 

Next time we will dive deeper into how OCD shows up in affective functioning. Get excited!

 

Sources:

American Psychiatric Association (2013). The diagnostic and statistical manual of mental disorders, fifth edition. Arlington, VA: American Psychiatric Association.

Harrison, B.J., Pujol, J., Cardoner, N., Deus, J., Alonso, Pl, Lopex-Sola, M., … Soriano-Mas, C. (2013). Brain corticostriatal systems and the major clinical symptom dimensions of obsessive-compulsive disorder. Society of Biological Psychiatry, 73, 321-328, doi: http://dx.doi.org/10.1016/j.biopsych.2012.10.006

Leckman, J.F., Grice, D.E., Boardman, J., Zhang, H., Vitale, A., Bondi, C., … Pauls, D.L. (1997). Symptoms of Obsessive-Compulsive Disorder. Am J Psychiatry, 154(7), 911-917, http://journals.psychiatryonline.org/data/Journals/AJP/3678/911.pdf

Stasik, S.M., Naragon-Gainey, K., Chmielewski, M., & Watson, D. (2012). Core OCD symptoms: Exploration of specificity and relations with psychopathology. Journal of Anxiety Disorders, 26, 859-870, doi: 10.1016/j.janxdis.2012.07.007

Steketee, G., Frost, R.O., & Cohen, I. (1998). Beliefs in obsessive-compulsive disorder. Journal of Anxiety Disorders, 12(6), 525-537, doi: 10.1016/S0887-6185(98)00030-9

Summers, B.J., Fitch, K.E., & Cougle, J.R. (2014). Visual, tactile, and auditory “not just right” experiences: Associations with obsessive-compulsive symptoms and perfectionism. Behavior Therapy, 45(5), 678-689. doi:http://dx.doi.org/10.1016/j.beth.2014.03.008

Tukel, R., Aydin, K., Ertekin, E., Ozyildirim, S.S., & Taravari, V. (2014). Proton magnetic resonance spectroscopy in obsessive-compulsvie disorder: Evidence for reduced neuronal integrity in the anterior cingulated. Psychiatry Research: Neuroimaging, doi:http://dx.doi.org/10.1016/j.pscychresns.2014.08.012

1 thought on “Neuroscience of Obsessive-Compulsive Disorder

  1. I am! I am excited! 🙂 Favorite example of compulsive behavior in my life: Checking and re-checking my pockets and person for any sign of metal objects before walking into the room holding the MRI machine (a huge magnet thus ferromagnetic metal = bad).

    I found myself wondering about the continuum that things like compulsions fall on. For example, someone diagnosed with OCD may have a very high level of compulsive behavior, so high that it disrupts daily life or causes a ton of distress but someone not diagnosed with OCD can also engage in compulsive behaviors, but perhaps to a lesser degree, which means less disruption or distress. I’m curious about the neural underpinnings– same neural system just different degrees of activation? Different neural systems?

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