Hippocampal abnormalities of glutamate/glutamine, <i>N</i>-acetylaspartate and choline in patients with depression are related to past illness burden
Bibliographic record
Abstract
BACKGROUND: Smaller hippocampal volumes in major depressive disorder (MDD) have been linked with earlier onset, previous recurrences and treatment refractoriness. The aim of our study was to investigate metabolite abnormalities in the hippocampus associated with past depressive illness burden. METHODS: Glutamate/glutamine (Glx), N-acetylaspartate (NAA) and choline (Cho), potential markers of glial/neuronal integrity and membrane turnover, respectively, were measured in adults with depression and healthy controls using a 3 T magnetic resonance spectroscopy scanner. Voxels were placed in the head of the right and left hippocampus. We controlled for systematic differences resulting from volume-of-interest (VOI) tissue composition and total hippocampal volume. RESULTS: Our final sample comprised a total of 16 healthy controls and 52 adult patients with depression in different stages of the illness (20 treatment-resistant/chronic, 18 remitted-recurrent and 14 first-episode), comparable for age and sex distribution. Patients with treatment-resistant/chronic and remitted-recurrent depression had significantly lower levels of Glx and NAA than controls, especially in the right hippocampal region (p ≤ 0.025). Diminished levels of Glx were correlated with longer illness duration (left VOI r = -0.34, p = 0.01). By contrast, Cho levels were significantly higher in patients with treatment-resistant/chronic depression than those with first-episode depression or controls in the right and left hippocampus (up to 19% higher; all p ≤ 0.025) and were consistently related to longer illness duration (right VOI r = 0.30, p = 0.028; left VOI r = 0.38, p = 0.004) and more previous episodes (right VOI r = 0.46, p = 0.001; left VOI r = 0.44, p = 0.001). LIMITATIONS: The cross-sectional design and the inclusion of treated patients are the main limitations of the study. CONCLUSION: Our results support that metabolite alterations within the hippocampus are more pronounced in patients with a clinical evolution characterized by recurrences and/or chronicity and add further evidence to the potential deleterious effects of stress and depression on this region.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".