# Temporal dynamics of inflammatory, platelet, and neurotrophic markers during social stress in relation to suicidal ideation and suicide attempt history

## TL;DR

This study explores how biological markers respond to social stress in people with depression and a history of suicidal thoughts or attempts.

## Contribution

The study reveals impaired dynamic responses in inflammatory, platelet, and neurotrophic systems during stress in individuals with suicidal ideation or attempts.

## Key findings

- Suicidal ideation was associated with elevated overall TNF-α levels.
- Participants with suicidal ideation showed blunted platelet activation responses to stress.
- BDNF increased linearly in participants with suicidal ideation or suicide attempts.

## Abstract

Interpersonal stress is a major precipitant of suicidal ideation (SI) and suicide attempts (SA), yet the underlying biological mechanisms remain unclear. This study examined dynamic plasma concentrations of inflammatory, platelet activation, and neurotrophic markers during acute social stress in 76 depressed women (mean age: 39.7 ± 1.39 years) with and without SA history or recent SI. Participants underwent the Trier Social Stress Test, with biomarkers measured at five time points before, during, and after the stressor. Covariate-adjusted growth curve models and area under the curve analyses were applied. SI was associated with elevated overall TNF-α levels (0.82 ± 0.05 vs. 0.61 ± 0.05, p = 0.039). Participants without SI showed cubic trajectories in TNF-α (t228 = 4.76, p < 0.001) and MIP-1β (t235 = 2.12, p = 0.035), and quadratic trajectories in platelet markers TSP-1 (t274 = −2.42, p = 0.016), PF-4 (t274 = −2.25, p = 0.025), and NAP-2 (t274 = −2.43, p = 0.016), which were absent in participants with SI. Cubic patters in inflammatory responses were also observed in participants without SA history, but not in suicide attempters (TNF-α: t228 = 3.15, p = 0.030; MIP-1β: t235 = 2.74, p = 0.007). Meanwhile, participants with SI or SA, but not those without, showed a linear BDNF increase (t275 = 2.39, p = 0.017; t275 = 2.28, p = 0.024, respectively). These findings suggest that SI and SA may be associated with impaired dynamic immune-inflammatory, platelet, and neurotrophic systems responses to acute interpersonal stress, reflecting systemic biological rigidity.

•Suicidal ideation was associated with elevated overall TNF-α levels.•Suicide attempters and ideators showed less dynamic inflammatory stress responses.•Platelet activation responses to stress were blunted in individuals with suicidal ideation.•BDNF increased linearly in participants with suicidal ideation or suicide attempts.•Findings suggest impaired biological flexibility under stress in suicidal individuals.

Suicidal ideation was associated with elevated overall TNF-α levels.

Suicide attempters and ideators showed less dynamic inflammatory stress responses.

Platelet activation responses to stress were blunted in individuals with suicidal ideation.

BDNF increased linearly in participants with suicidal ideation or suicide attempts.

Findings suggest impaired biological flexibility under stress in suicidal individuals.