Psychobiology of suicidal behavior in combat veterans
Leo Sher, M.D.
Our research article, “Dehydroepiandrosterone and dehydroepiandrosterone sulfate levels in combat veterans with or without a history of suicide attempt” has been published in Acta Psychiatrica Scandinavica online ahead of print (1). The objective of our investigation was to test the hypothesis that combat veterans who have made a suicide attempt postdeployment can be distinguished from combat veterans who have never made a suicide attempt based on differences in clinical and biological variables. For the latter, we focused on dehydroepiandrosterone (DHEA) and dehydroepiandrosterone sulfate (DHEAS), neuroendocrine markers that are related to stress.
Demographic and clinical parameters of combat veterans who have made a suicide attempt postdeployment and combat veterans who have never made a suicide attempt were assessed and recorded. Blood samples were assayed for DHEA and DHEAS.
We have observed that suicide attempters had higher Scale for Suicidal Ideation and Montgomery – Asberg Depression Rating Scale (MADRS)—suicidal thoughts item scores in comparison with non-attempters at the time of study entry. There was a trend toward higher MADRS scores in the suicide attempter group compared with non-attempters.
We have also found that suicide attempters had significantly lower levels of DHEA and DHEAS compared with non-attempters. DHEAS levels negatively correlate with Scale for Suicidal Ideation scores in suicide non-attempters but not in suicide attempters. DHEA/DHEAS ratios positively correlate with total adolescence aggression scores, total adulthood aggression scores, and total aggression scale scores in suicide attempters but not in suicide non-attempters.
Our study showed that combat veterans with a previous a history of suicide attempt continue to demonstrate higher suicidal ideation in comparison to combat veterans without a history of suicide attempt. This indicates that combat veterans with a history of suicide attempt are at an elevated suicide risk long after suicide attempt.
The fact that higher DHEAS levels are associated with lower suicidality among suicide nonattempters is consistent with research data suggesting that DHEAS has neuroprotective effects. The fact that this association is not observed in suicide attempters may indicate that this protective system is dysregulated in suicide attempters. We can hypothesize that as psychiatric disorders progress, the level of DHEAS declines and thus the neuroprotection provided by DHEAS is considerably diminished or lost leading to increased suicidality.
Reference
1. Sher L, Flory J, Bierer L, Makotkine I, Yehuda R. Dehydroepiandrosterone and dehydroepiandrosterone sulfate levels in combat veterans with or without a history of suicide attempt. Acta Psychiatr Scand. 2018 May 22. doi: 10.1111/acps.12897. [Epub ahead of print]