written by: Kelly Marquize
• edited by: Paul Arnold
• updated: 12/18/2010
Researchers have made some exciting discoveries about the role of glutamate in OCD. With the help of imaging, scientists have learned that glutamate levels are higher in persons with OCD. This article explores these findings and what they mean.
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What is Glutamate?
Glutamate is the main neurotransmitter in the nervous system and one of 20 amino acids that are needed to make proteins; it is responsible for mediating the excitatory signals in the nervous system.
Most importantly, glutamate is directly linked to normal brain functions such as memory, learning, and cognition (Danbolt, 2001). A delicate balance of glutamate must be maintained; although it is needed for healthy brain functions, too much can be toxic. Glutamate accounts for about 40% of the nerve signals in the brain.
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Glutamate OCD Research
Ongoing research is being conducted to determine if and how glutamate levels contribute to OCD. Although the study of glutamate and OCD is relatively new, there have been some exciting discoveries that hold promise for future treatment of OCD. It would appear that science is on the threshold of decoding OCD. The following information is based on the data collected from some of these studies.
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So far, studies have shown that there is clear difference between glutamate levels in individuals with OCD and those without the disorder. Researchers believe that this difference in levels may contribute to the obsessive and compulsive behaviors found in OCD.
One such study focuses on a glutamate transporter gene called SLC1A1. This particular gene regulates the flow of glutamate in the brain. “Variations in the gene might lead to alterations in that flow, perhaps putting a person at increased risk of developing OCD" (Gavin, 2006). This gene is the only one that has been consistently linked to OCD.
The most compelling evidence, thus far, supporting the role of glutamate in OCD comes from researchers at the Ruhr University in Germany. Here, they studied the cerebrospinal fluid (CSF) of individuals with OCD and compared it to that of healthy individuals. The findings revealed that glutamate levels were higher in those with OCD (Bloch, Coric, & Pittenger, 2010).
Numerous other studies have been conducted that reveal higher levels of glutamate in OCD patients. They have included the use of SPECT scans, PET scans, and fMRI imaging; each time showing more concentrated levels of glutamate.
Other methods of research include using glutamate-modulating agents which reduce the amount of glutamate that is released in the brain. These medications have been shown to reduce OCD symptoms in clinical trials, thus supporting the hypothesis that high levels of glutamate are related to OCD.
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While data suggests that glutamate is linked to OCD, it is not yet understood how. The role of glutamate in OCD needs further research before any real assumptions can be made. To date, it is unclear if abnormal glutamate levels are the cause of OCD or just a byproduct of the disorder. There is no question that there is some connection between glutamate levels and OCD, but for now researchers can only speculate as to what this connection is.
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Bloch, M. H., Coric, V., & Pittenger, C. (2010). New horizons in OCD research and the potential importance of glutamate: Can we develop treatments that work better and faster? Retrieved December 12, 2010, from http://www.ocfoundation.org/glutamate.aspx