Blood biomarker changes in response to low-dose oral ketamine treatment in adults with major depressive disorder (MDD) and post-traumatic stress disorder (PTSD)
Annette M Braxton, Christina Driver, Daniel F. Hermens, Bonnie L. Quigley
medRxiv August 14, 2026 preprint DOI: 10.64898/2026.08.12.26360216 (opens in new tab)
Study at a glance
AI-extracted from the abstract| Characteristics | Observational cohort |
|---|---|
| Sample size | 35 |
| Population | Adults with MDD alone or comorbid MDD+PTSD |
| Intervention | Low-dose oral ketamine |
| Dose | low-dose (not further specified) |
| Topics | Depression Esketamine Ketamine PTSD |
| Key findings | Low-dose oral ketamine treatment was associated with improvements in depression, anxiety, stress, social functioning, suicidal ideation, and well-being in both MDD and MDD+PTSD groups, with no detectable difference in biological response between groups. Blood levels of BDNF and VEGF-A decreased post-treatment. |
Abstract
Abstract Major depressive disorder (MDD) and post-traumatic stress disorder (PTSD) are prevalent, chronic, and disabling mental health conditions which are difficult to treat. Ketamine has demonstrated effect for improving depression and PTSD symptoms independently but reports often overlook focused comorbid improvement of these symptoms within individuals. To address this, we assessed blood-based biomarker and psychological changes following low-dose oral ketamine treatment for adults with MDD alone (n=14) and comorbid MDD+PTSD (n=21). Before treatment, the MDD clinical group presented with more severe depression, lower serotonin levels and higher kynurenine levels than the MDD+PTSD group. Post-treatment there were no detectable differences in the biological response between clinical groups, with combined analysis revealing common decreases in circulating brain-derived neurotrophic factor (BDNF) and vascular endothelial growth factor (VEGF-A). Additionally, post-treatment, both clinical groups showed improvements in anxiety, stress, social functioning, suicidal ideation, and general well-being measures, as well as individual improvements in depression scores and PTSD symptoms in the MDD- and PTSD-containing groups, respectively. Collectively, this study presents additional evidence that low-dose oral ketamine treatment can be effective for MDD and MDD+PTSD, individually and comorbidly, and that both MDD and PTSD clinical groups responded in the same biological manner. Highlights Low dose oral ketamine can be effective in treating MDD and PTSD concurrently Blood biomarkers BDNF and VEGF decreased with symptom improvement No detectable difference in oral ketamine treatment response by clinical diagnosis
In the evidence
This study is part of the evidence base for 2 syntheses in the library. Here is how each one recorded it.
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Low-dose oral ketamine was associated with improvements in depression, anxiety, stress, social functioning, suicidal ideation, and well-being in both groups, with no detectable difference in biological response between groups.
Synthesized
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State of the evidence: PTSD Supports
Low-dose oral ketamine treatment was associated with improvements in depression, anxiety, stress, social functioning, suicidal ideation, and well-being in both MDD and MDD+PTSD groups, with no detectable difference in biological response between groups.
Synthesized
Comparable studies
Other observational and cohort studies on ketamine for PTSD, most cited first.