Leo Sher, M.D.

Our research paper, “Endogenous cannabinoid levels and suicidality in combat veterans” has been published in Psychiatry Research online ahead of print (1). The goal of our study was to test the hypothesis that combat veterans who have made a suicide attempt post-deployment can be distinguished from combat veterans who have never made a suicide attempt based on differences in psychological and biological variables. For the latter, we focused on endogenous cannabinoids, neuroendocrine markers that are associated with stress.

Combat veterans with or without a history of post-deployment suicide attempts were enrolled in the study. Only suicide attempters who made an attempt within 5 years prior to the day of evaluation were included in the attempter group. Suicide attempts were defined as self-destructive acts with the intent to end one’s life. Demographic and clinical parameters of suicide attempters and non-attempters were assessed. Blood samples were assayed for anandamide (AEA), 2-arachidonoylglycerol (2-AG), and cortisol.

There was no difference between the groups with regard to demographic parameters: age, gender, marital status, and percentage of subjects who completed at least four-year college. Suicide attempters had higher Scale for Suicidal Ideation (SSI) scores in comparison to non-attempters. Controlling for gender, 2-AG levels were higher among suicide attempters in comparison to non-attempters. Cortisol levels positively correlated with 2-AG levels and negatively correlated with SSI scores among non-attempters but not among attempters. AEA levels negatively correlated with SSI scores among attempters but not among non-attempters.

Our results indicate that there are psychological and biological differences between combat veterans with or without a history of suicidal attempt. Our findings also suggest that clinically observed differences between the groups may have a neurobiological basis. Further studies of the role of endocannabinoids in the pathophysiology of suicidal behavior may contribute to our understanding of the neurobiology of suicide.

Reference

1. Sher L, Bierer LM, Flory J, Hill MN, Makotkine I, Yehuda R. Endogenous cannabinoid levels and suicidality in combat veterans. Psychiatry Res. 2019 Jul 25:112495. doi: 10.1016/j.psychres.2019.112495. [Epub ahead of print]