Résumé
Background: Bipolar disorder (BD) and schizophrenia-spectrum disorders (SZ) are associated with high rates of suicidal ideation (SI) and suicide attempts (SA). Peripheral immune-vascular abnormalities may contribute to suicidal vulnerability in these disorders, but their specificity, temporal meaning, and diagnostic patterning remain unclear. Methods: We quantified 28 peripheral immune-vascular variables (cytokines/chemokines, vascular-injury markers, blood counts, lipids) in 980 French FACE (FondaMental Advanced Centres of Expertise) outpatients with BD (n = 529) or SZ (n = 451). Elastic-net logistic regression and partial least-squares regression for binary outcomes examined associations with SA, baseline SI, and SI over 12 months in pooled and diagnosis-stratified samples. Models adjusted for age, sex, and body mass index, with sensitivity analyses for depression severity, medication classes, smoking, phenotype overlap, attrition, and missing data. Results: In pooled analyses, SA was associated with higher vascular endothelial growth factor; stratified analyses suggested this signal was mainly driven by BD (OR = 1.33, 95% CI 1.08-1.64). In SZ, SA showed weaker platelet/SAA-related associations. Baseline SI showed more consistent multivariate signals than individual analytes; in BD, higher IL-7 and SAA remained associated with SI after adjustment, whereas SZ findings were more medication-sensitive. SI over 12 months showed the least stable associations; in BD, lower IL-7 was associated with follow-up SI (OR = 0.72, 95% CI 0.54-0.96). Internal validation indicated stronger performance for baseline SI than for SA or follow-up SI. Conclusions: We found modest, phenotype-dependent and partly diagnosis-specific peripheral immune-vascular correlates of SI and SA in BD and SZ. Replication and direct biological validation are needed.