Combat-exposed war veterans at risk for suicide show hyperactivation of prefrontal cortex and anterior cingulate during error processing

Abstract

Objective: Suicide is a significant public health problem. Suicidal ideation (SI) increases the risk for completed suicide. However, the brain basis of SI is unknown. The objective of this study was to examine the neural correlates of self-monitoring in individuals at risk for suicide. We hypothesized that combat veterans with a history of SI relative to those without such a history would show altered activation in the anterior cingulate cortex and related circuitry during self-monitoring. Methods: Two groups of combat-exposed war veterans (13 men with and 13 men without history of SI) were studied. Both the SI and non-SI participants had two or more of the following: a) current major depressive disorder, b) current posttraumatic stress disorder, and c) history of mild traumatic brain injury, and each subject performed a validated stop task during functional magnetic resonance imaging. Error-related activation was compared between the SI and non-SI groups. Results: The SI group demonstrated more error-related activation of the anterior cingulate (8256 mm3, t = 2.51) and prefrontal cortex (i.e., clusters >2048 mm 3, voxelwise p < .05). The SI and non-SI participants showed similar behavioral task performance (i.e., mean error rate, F values < 0.63, p values > .43; and mean reaction times, F = 0.27, p = .61). Conclusions: These findings suggest neural correlates of altered self-monitoring in individuals with a history of SI and may further suggest that functional magnetic resonance imaging could be used to identify individuals at risk for suicide before they engage in suicidal behavior. Abbreviations: SI = suicidal ideationACC = anterior cingulate cortexOEF = Operation Enduring FreedomOIF = Operation Iraqi FreedomfMRI = functional magnetic resonance imagingTBI = traumatic brain injuryMDD = major depressive disorderPTSD = posttraumatic stress disorderAFNI = Analysis of Functional NeuroimagesPFC = prefrontal cortex © 2012 by the American Psychosomatic Society.