Biomarkers for combat-related PTSD: focus on molecular networks from high-dimensional data.

OBJECTIVES

Fibromyalgia (FM) and post-traumatic stress disorder (PTSD) share key clinical features, including sleep disturbance, fatigue, cognitive symptoms and affect dysregulation, yet they are classified as distinct disorders. We examined whether FM and PTSD represent separable phenotypes or overlapping stress-related symptom profiles using a distributional similarity approach.

METHODS

In an international cross-sectional online survey of adults aged 18-65 years, participants with a self-reported clinical diagnosis of FM or PTSD, and healthy controls, completed validated measures of somatic symptom burden, trauma-related symptoms, psychological vulnerability traits, comorbidities, and emotional activation patterns (EASEL-3). Case definitions were operationalised using established thresholds for polysymptomatic distress and PTSD symptom severity. To address unequal group sizes and reduce case-definition circularity, we applied adaptive sub-sampling with bootstrap resampling and quantified between-group similarity using Hellinger distance, complemented by stability analyses.

RESULTS

Across somatic, psychological and affective domains (threat, drive and soothing systems), FM and PTSD showed substantial overlap with limited discriminatory capacity, while both differed clearly from healthy controls. Nearly half of participants meeting criteria for one condition also met criteria for the other, indicating high co-occurrence.

CONCLUSIONS

These findings question the strict nosological separation of FM and PTSD and are compatible with a spectrum model of stress-related disorders. They further suggest that systematic trauma assessment and integrated, mechanism-based treatment strategies should be considered in the management of both conditions.