Higher levels of glutamate and altered glutmate signaling have been linked to the development of Obsessive Compulsive Disorder. It is thought that the high levels of glutamate in response to immune/microglial activation could be a large contributer to the imblanance. Though the connection is still being explored, glutamate-modualting drugs are being targeted as a treatment. Personally, this makes a lot of sense as you often see higher levels of OCD in those with chronic underlying infections (PANS, PANDAS, Lyme, etc..) and immune activation.
Herbal Medicine in the Treatment of Obsessive Compulsive Disorder: A Review
This is not a comprehensive list, simply some articles I have found along the way.
Recent news report “As well as their link with serotonin, the mutations are also involved in synapses – where brain cells connect with each other – and in the production of glutamate. This is another neurotransmitter critical to communication between nerve cells. Higher levels have been found in OCD patients.” “These genes act in neural pathways linked to OCD, including serotonin and glutamate signalling and synaptic connectivity, suggesting potential therapeutic targets.’ http://www.dailymail.co.uk/health/article-4988886/Genes-cause-OCD-identified-scientists.html
“Compelling research has linked excess glutamate stimulation and/or elevations of proinflammatory cytokines to a number of neuropsychiatric and behavioral conditions, many of which are seen with CTE. These include panic attacks, aggressive behavior, suicide, obsessive-compulsive disorder, anxiety, and depression.[39,54,112,162,236,243]” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3157093/
“The precise role of glutamate dysregulation in OCD remains unclear, and we lack blinded, well-controlled studies demonstrating therapeutic benefit from glutamate-modulating agents. Nevertheless, the evidence supporting some important perturbation of glutamate in the disorder is increasingly strong” https://www.ncbi.nlm.nih.gov/m/pubmed/21963369/
“Furthermore, these results provide support for the role of altered glutamatergic neurotransmission in the pathogenesis of OCD.” https://jamanetwork.com/journals/jamapsychiatry/fullarticle/209779
“This, in turn, increased the excitability of direct SPNs, leading the team to suspect that mGluR5 may well be the guilty party behind OCD, as it appears to control the hyperactivity of the brain circuits that coordinate action.Based on this discovery, the researchers injected the mice with a chemical that deactivates mGluR5 receptors, and rather incredibly found that their OCD behavior disappeared within minutes. “The reversibility of the symptoms was immediate – on a minute time frame,” explained study co-author Nicole Calakos in a statement” http://www.iflscience.com/brain/brain-receptor-responsible-ocd-identified/“Obsessive compulsive disorder and the glutamatergic system. Available from: https://www.researchgate.net/publication/258854482_Obsessive_compulsive_disorder_and_the_glutamatergic_system[accessed Nov 04 2017].”