Abstract:
Dysregulation of the stress axis and low-grade inflammation may contribute to suicidal thoughts and acts in
borderline personality disorder. Evidence synthesis (2020–2025) of narrative/systematic reviews and large
observational studies in adults. Biomarkers included circulating and hair cortisol, diurnal cortisol profiles and
dexamethasone paradigms, alongside inflammatory indices (C-reactive protein, interleukin-6, tumor necrosis
factor). Outcomes were suicidal ideation, suicide attempts, suicide deaths, and self-harm. Inflammatory
markers are consistently higher in borderline personality disorder with suicidality, with small-to-moderate
between-group differences most frequently reported for C-reactive protein and interleukin-6. Findings for the
stress axis are heterogeneous: several studies show flatter diurnal cortisol slopes or lower hair cortisol in
suicidal subgroups, while acute suppression tests identify a non-suppressing subset with elevated risk.
Associations generally persist after adjustment for depressive symptoms, though effect sizes attenuate and
prospective data remain limited. Combining inflammatory and stress-axis measures improves discrimination
over single markers, but calibration is variable across settings. Overall, biomarkers show additive, clinically
meaningful signals yet lack standardized cut-offs and external validation. Research priorities include
harmonized sampling protocols, preregistered prospective cohorts, and integration with sleep, impulsivity, and
digital phenotypes to refine short-term risk stratification.
