Swedish researchers have now presented new research findings in the journal Neuropsychopharmacology that show that glutamate, which is also believed to play a role in depression, is linked to suicidal tendencies. Lena Brundin from Lund University and Sophie Erhardt from Karolinska Institutet have spent several years studying how inflammation can lead to mental illness, and the study is a result of these projects.
“The findings are very important because they show a chemical disease mechanism in the patients. There has been a major focus on another signal substance, serotonin, for 40 years. Our conclusions suggest that it is time to shift some of the focus to glutamate”, says Lena Brundin.
The researchers studied the activity of glutamate by measuring quinolinic acid – a chemical substance that increases the signal strength in the glutamate system – in the spinal fluid of 100 people. Around two thirds of the participants had been admitted to hospital following a suicide attempt, while the remainder were healthy. The results showed that the levels of quinolinic acid in the suicidal patients were over twice as high as those in the healthy subjects. The patients who were reported to show the most pronounced suicidal behaviour also had the highest levels.
“Anti-glutamate drugs are still under development and could become an important tool to prevent suicides. New clinical studies have shown that the anaesthetic substance ketamine, which blocks glutamate signalling, appears to be very effective against depression, even if its side-effects limit its application at present”, says Lena Brundin.
The research report, ‘Connecting inflammation with glutamate agonism in suicidality’, is a collaboration between researchers from Sweden, the USA and Australia.
Authors: Sophie Erhardt, Chai K. Lim, Klas R. Linderholm, Shorena Janelidze, Daniel Lindqvist, Martin Samuelsson, Kristina Lundberg, Teodor T. Postolache, Lil Träskman-Bendz, Gilles J. Guillemin and Lena Brundin.
Title: ‘Connecting inflammation with glutamate agonism in suicidality’ Neuropsychopharmacology, 2012; doi: 10.1038/npp.2012.248
Lena Brundin, Specialist in Psychiatry, Reader at the Department of Clinical Sciences, Lund University, Sweden, and Associate Professor in Experimental Psychiatry at the College of Human Medicine, Michigan State University, USA.
Tel: +1 616 808 6432, Email: Lena.Brundin@med.lu.se
Sophie Erhardt, Reader at the Department of Physiology and Pharmacology, Karolinska Institutet. Tel: +46 8 524 868 83, Email: Sophie.Erhardt@ki.se