Lack of relationships between ketamine treatment and peripheral neurotrophic and inflammatory factors in a randomized controlled ketamine trial of major depressive disorder.
Study Goal
The researchers aimed to investigate whether peripheral blood neurotrophic and inflammatory factors (NIFs) are linked to ketamine's antidepressant effects in adults with treatment-resistant depression (TRD).
Results Summary
The study found no significant associations between ketamine treatment and peripheral NIF levels, except in individuals with lower BMI, where increased IL-1RA levels were linked to worse immediate treatment response. Overall, ketamine did not show detectable effects on NIF trajectories or their relationship with depression outcomes.
Population
133 adults with treatment-resistant depression (TRD).
Effective Dosage
Single-dose infusion of 0.5 mg/kg ketamine.
Duration
Five-day post-infusion period.
Interactions
None mentioned
| Intervention | Direction | Endpoint | Population | Dosage | Impact | Claim # |
|---|---|---|---|---|---|---|
single-dose infusion of ketamine (0.5 mg/kg) | no change | NIF trajectories | 133 adults with treatment-resistant depression (TRD) | no significant change | No differences were found | #1 |
single-dose infusion of ketamine (0.5 mg/kg) | no change | associations of NIF and depression trajectories | 133 adults with treatment-resistant depression (TRD) | no significant change | No differences were found | #2 |
single-dose infusion of ketamine (0.5 mg/kg) | no change | associations of baseline NIF levels and depression trajectories | 133 adults with treatment-resistant depression (TRD) | no significant change | No differences were found | #3 |
single-dose infusion of ketamine (0.5 mg/kg) | decrease | depression | participants with lower BMI (BMI < 25) | - | increasing interleukin-1 receptor antagonist (IL-1RA) trajectories post-ketamine were associated with less improvement | #4 |
single-dose infusion of ketamine (0.5 mg/kg) | decrease | depression | individuals with low BMI | - | increases in IL-1RA levels may be linked to worse immediate treatment response | #5 |
BACKGROUND: Ketamine is a rapid-acting treatment for treatment-resistant depression (TRD), though mechanisms related to ketamine's effects remain unclear. Blood-based neurotrophic and inflammatory factors (NIFs; e.g., brain-derived neurotrophic factor, interleukin-6) have emerged as markers potentially linked to ketamine and ketamine treatment response. METHODS: In this secondary analysis of a randomized controlled trial (RCT), 133 adults with TRD received a single-dose infusion of ketamine (n = 89; 0.5 mg/kg) or saline (n = 44) and provided measures of peripheral blood NIF levels and depression severity across a five-day post-infusion period. Differences between ketamine and saline groups were examined for (1) NIF levels, (2) associations between NIF trajectories and depression score trajectories, and (3) associations between baseline NIF levels and depression score trajectories. Subgroup sensitivity analyses examined identical relationships within many (n = 28) discrete subgroups of individuals. RESULTS: No differences were found between ketamine and saline cohorts for NIF trajectories, associations of NIF and depression trajectories, or associations of baseline NIF levels and depression trajectories. On subgroup analyses, in participants with lower BMI (BMI < 25; n = 66), increasing interleukin-1 receptor antagonist (IL-1RA) trajectories post-ketamine were associated with less improvement in depression in the first day post-infusion. DISCUSSION: Associations between ketamine treatment and peripheral neurotrophic/inflammatory factors were not detected in our RCT of 133 adults with TRD. The sole exception across exhaustive sensitivity analyses was that, in individuals with low BMI, increases in IL-1RA levels may be linked to worse immediate treatment response. Future research investigating CNS-specific NIF activity is needed to more definitively test the posited role of NIFs in ketamine's antidepressant mechanisms.