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What Is Dopamine?
Before we get into the role that dopamine plays in obsessive-compulsive disorder (OCD), we must first understand what dopamine is. Dopamine is a chemical that is produced in our bodies and is just one of the many neurotransmitters in the brain. These neurotransmitters are responsible for communicating information throughout our bodies - information such as emotional responses, pleasure, pain, cognitive skills, movement, and impulses. It is helpful to think of these neurotransmitter’s as scales; when the neurotransmitters are balanced, then all is well. However, when they are not in balance, then problems can arise—problems such as OCD.
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Dopamine and OCD
OCD is characterized by obsessive thought patterns that cause extreme anxiety. These thoughts (i.e. fear of germs, hand washing, flipping light switches, etc.) drive the individual to bring them to fruition by completing the tasks they obsess about. They fear that if these tasks, or rituals, are not carried out, then something catastrophic will happen. Engaging in these rituals brings temporary relief to their anxiety and can cause a sense of pleasure.
Knowing that dopamine has a direct relationship to the pleasure principle and impulses, scientists began researching the role that dopamine plays in OCD. Using PET scans and other types of imaging, researchers have indeed found that there is an over-production of dopamine in individuals with OCD.
In one study, the dopamine transporter density of 15 OCD subjects was compared to that of 19 healthy subjects. Results showed that dopamine levels were higher in the OCD subjects leading researchers to concur that dopamine plays a direct role in the pathophysiology of OCD (Kim et. al, 2003). This was even further confirmed when serotonin reuptake inhibitors (SRIs) were administered and compulsive behaviors were reduced.
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The Pathophysiology of OCD
To delve a little deeper, we can look at the pathophysiology of OCD. While the exact pathophysiology of OCD has not yet been identified, there has been some compelling evidence suggesting that there are abnormalities in dopaminergic transmissions. Scientists believe that transmissions of dopamine are increased in OCD, leading to over-stimulation (Lundbeck Institute, 2000).
Certain parts of the brain, namely the basal ganglia and the frontal cortex, work together to guide behaviors. When there is too much activity in the basal ganglia area, then an over-production of dopamine occurs. Bill Harris (2010), director of the Centerpointe Research Institute, says that another part of the brain affected is called the cingulate gyrus, “which has a lot to do with a person's ability to shift attention, be cognitively flexible, to adapt to circumstances, to move easily from one idea to another, to "go with the flow," and to be cooperative.”
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Dopamine and OCD: Tying It All Together
So what does this all mean? In short, dopamine is an essential chemical that is needed for proper brain function; however too much can lead to problems such as OCD. Scientists know for a fact that dopamine helps control impulses, emotional responses, and an array of other functions. They also know that abnormal levels of dopamine can interfere with said functions. Thus, scientists hypothesize that dopamine levels are tied to OCD. More research needs to be conducted to cement this theory. But for now, the information that has surfaced sounds promising in finding real help for those who suffer with OCD.
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Harris, B. (2010). A letter to someone with obsessive-compulsive disorder. Retrieved December 10, 2010, from http://chetday.com/ocd-obsessivecompulsivedisorder.htm
Kim, C. H., Koo, M. S., Cheon, K. A., Ryu, Y. H., Lee, J. D., & Lee, H. S. (2003). Dopamine transporter density of basal ganglia. European Journal of Nuclear Medicine and Molecular Imaging, 30, 1637-1643. Retrieved December 10, 2010, from http://www.ingentaconnect.com/content/ftd/ern/2010/00000010/00000002/art00012
Lundbeck Institute (2000). The dopamine pathways in OCD. Retrieved December 9, 2010, from http://www.cnsforum.com/imagebank/item/Neuro_path_DA_OCD/default.aspx