Progesterone and suicidality in male combat veterans

Studies suggest that progesterone may influence mood and behavior in men. We hypothesized that progesterone is associated with suicidal ideation and attempts in men. We examined morning baseline progesterone levels and the effect of dexamethasone administration on progesterone levels in male combat veterans with or without a history of suicide attempt.

Demographic and clinical parameters of the study participants were assessed and recorded. Study participants were interviewed by a trained clinician using the Mini-International Neuropsychiatric Interview, the Montgomery-Åsberg Depression Rating Scale, the Scale for Suicidal Ideation, the Brown-Goodwin Aggression Scale and the Reasons for Living Inventory. Blood samples to determine progesterone levels were collected in the morning on the day prior to and following dexamethasone ingestion.

Baseline progesterone levels were higher in suicide non-attempters in comparison to attempters. In the whole sample, higher baseline progesterone levels were associated with lower suicidal ideation, lower depression and more reasons not to die by suicide. Progesterone levels decreased after dexamethasone administration among non-attempters but not among attempters. Progesterone levels before and after dexamethasone administration positively correlated with aggression among non-attempters but not among suicide attempters.

Our study is the first demonstration of progesterone non-suppression by dexamethasone in suicide attempters. The results of our study underline the significant role of neurobiological mechanisms in the pathophysiology of suicidal behavior in combat veterans. Studies of the relation between neurosteroid function and suicidal behavior may lead to the development of biomarkers for suicidality and facilitate identification of individuals at high suicide risk.