Posttraumatic stress disorder (PTSD) is an important risk factor for suicidal ideation and attempts, as well as death by suicide. Because little is known about the biology underlying suicide in PTSD, there are limited pharmacologic options to treat PTSD patients at high risk of suicide.

Researchers report that the metabotropic glutamatergic receptor 5 (mGluR5) might serve as a potential biomarker for intervention and suicide risk management in PTSD.

Using positron emission tomography (PET), the authors quantified mGluR5 density in five brain regions in 29 individuals with PTSD, 29 participants with major depressive disorder (MDD), and 29 healthy controls.

The authors found that mGluR5 availability in individuals with PTSD was significantly higher in all five brain regions, compared with healthy controls, as well as in three brain regions, compared with individuals with MDD. In particular, mGluR5 upregulation in all five brain regions was associated with self-reported suicidal ideation on the day of the brain scan in individuals with PTSD, but not in individuals with MDD.

Moreover, higher mGluR5 availability was associated with mood disturbances in the PTSD group, but lower mGluR5 availability was associated with mood disturbances in the MDD group.

According to the authors, the findings suggest that downregulating mGluR5 might decrease suicidal ideation and related symptoms in individuals with PTSD.

https://www.pnas.org/content/early/2019/05/07/1818871116