Posttraumatic stress disorder (PTSD) is increasingly recognized as a chronic neurobiological condition involving dysregulated stress circuitry, systemic inflammation, and sleep disturbances implicated in neurodegeneration. Epidemiological evidence suggests an association between PTSD and dementia risk; however, effect estimates vary across populations. The objective of this study was to quantify the association between PTSD and incident dementia using longitudinal cohort data and random-effects meta-analysis. A systematic search of PubMed was conducted from inception to December 25, 2025, following Preferred Reporting Items for Systematic Reviews and Meta-Analyses 2020 guidelines. Longitudinal cohort studies assessing clinically diagnosed PTSD and reporting hazard ratios (HRs) for incident dementia were included in the study. Fully adjusted HRs were pooled using restricted maximum likelihood (REML) random-effects models. Heterogeneity was assessed using I 2 and τ 2 . Mixed-effects meta-regression examined study-level moderators. Publication bias and sensitivity analyses were performed. Twelve cohort studies were included, comprising veteran and general population samples across multiple regions. PTSD was associated with an increased risk of dementia (pooled HR = 1.75, 95% confidence interval: 1.55–1.97; P < 0.001). Substantial heterogeneity was observed ( I 2 = 93.9%). The 95% prediction interval (1.21–2.52) indicated persistence of the association across comparable settings. Subgroup analyses showed similar effects across populations, and meta-regression identified no significant moderators. Trim-and-fill minimally altered the estimate (HR ≈ 1.70), and sensitivity analyses confirmed robustness. PTSD is associated with a clinically meaningful increase in dementia risk. These findings support its role as a long-term neurocognitive vulnerability and highlight the importance of early identification and risk-reduction strategies.
Sulejmani et al. (Thu,) studied this question.
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