Blunted arginine vasopressin secretion in individuals experiencing a major depressive episode with comorbid post-traumatic stress disorder: Results from an exploratory study using copeptin as a surrogate marker.
Journal of neuroendocrinology January 1, 2026 Hiroe Hu, Yoojin Lee, Alaina N Tillman et al. 1 citation
People with both major depression and post-traumatic stress disorder (PTSD) have lower baseline levels of copeptin, a stable marker of vasopressin secretion, and a blunted reduction in copeptin after a single low-dose ketamine infusion compared to those with depression alone. Copeptin levels were unrelated to depression diagnosis or symptom severity of depression, anxiety, PTSD, anhedonia, suicidal ideation, or childhood trauma, but higher copeptin was linked to verbal aggression, an association weakened by PTSD. These findings point to a possible biological subtype of reduced vasopressin activity in co-occurring depression and PTSD, suggesting copeptin may serve as a peripheral biomarker for central vasopressin-driven circuits in neuropsychiatric disorders.