Cortical inhibitory markers of lifetime suicidal behavior in depressed adolescents
Bibliographic record
Abstract
Although suicide is the second-leading cause of death in adolescents and young adults worldwide, little progress has been made in developing reliable biological markers of suicide risk and suicidal behavior. Converging evidence suggests that excitatory and inhibitory cortical processes mediated by the neurotransmitters glutamate and γ-aminobutyric acid (GABA) are dysregulated in suicidal individuals. This study utilized single- and paired-pulse transcranial magnetic stimulation (TMS) to assess excitatory and inhibitory cortical functioning in healthy control adolescents ( n = 20), depressed adolescents without any history of suicidal behavior (“Depressed”, n = 37), and depressed adolescents with lifetime history of suicidal behavior (“Depressed+SB”, n = 17). In a fixed-effects general linear model analysis, with age, sex, and depression severity as covariates, no significant group main effects emerged for resting motor threshold, intracortical facilitation, short-interval intracortical inhibition, or cortical silent period. However, group main effects were significant for long-interval intracortical inhibition (LICI) at interstimulus intervals (ISIs) of 100 ms and 150 ms, but not 200 ms. Depressed+SB adolescents demonstrated impaired LICI compared to healthy control and Depressed adolescents, while healthy control and Depressed participants did not differ in LICI. Multiple linear robust regression revealed significant positive linear relationships between lifetime suicidal behavior severity and impairment in LICI at 100-ms and 150-ms ISIs. In a post hoc receiver operating characteristic analysis, LICI significantly discriminated Depressed from Depressed+SB youth in 100-ms and 150-ms paradigms. These findings suggest that GABA B receptor-mediated inhibition is distinctly dysregulated in depressed adolescents with histories of suicidal behavior. Further research is warranted to establish the utility of cortical inhibition in the assessment of suicide risk and as a target for treatment interventions.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| 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 | 0.001 |
| 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 teacher head, 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".