Converging lines of evidence from neuroimaging, genetic and pharmacological studies support the importance of glutamate abnormalities in the pathogenesis of OCD. In Magnetic Resonance Spectroscopy studies elevated concentrations of glutamate and related compounds have been demonstrated in the caudate nucleus and orbitofrontal cortex of OCD patients compared to normal controls. In genetic studies, single nucleotide polymorphisms within the glutamate transporter gene SLC1A1 have been associated with the diagnosis of OCD. Open-label, pharmacological treatment studies have suggested that glutamate modulating agents such as riluzole, n-acetylcysteine and memantine may be effective in the treatment of OCD.