Suicidal ideation, depression, hopelessness, psychological pain, and traumatic stress are all elevated during a suicide crisis and respond to a single ketamine infusion. In a study of 118 adults spanning the suicide risk continuum, 14 high-risk individuals who had recently attempted or seriously considered suicide were compared with those whose crisis had resolved. A subset of 10 high-risk participants received open-label ketamine (0.5 mg/kg). Results were mixed depending on the assessment used, but all five clinical characteristics were elevated near the time of crisis and decreased after ketamine. The small sample and use of only one intervention limit the findings.
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.