Inflammatory Markers in Tears Can Signal Depression, PTSD-Anxiety

Inflammatory markers found in tear samples can help establish levels of depression and posttraumatic stress disorder (PTSD)-associated anxiety symptoms, say investigators of a study presented at the Association for Research and Vision in Ophthalmology (ARVO) Annual Meeting in New Orleans, Apr 23–27, 2023. Tear biomarkers may be a potential noninvasive mental health diagnosis or treatment evaluation tool.

Researchers prospectively recruited 39 volunteers from the Miami Veterans Affairs (VA) Healthcare System eye clinic. Participants completed the depression symptom assessment, Patient Health Questionnaire 9 (PHQ-9); and a survey of PTSD-related anxiety, the Post Traumatic Stress Disorder Checklist–Military Version (PCL-M). Veterans in this study were an average of 61±13 years of age. The cohort self-identified as 95% male, 69% Black, and 15% Hispanic. 

Objective examinations considered in this research included Schirmer testing and tear protein analysis. Researchers identified inflammatory markers using a custom-designed multiplex assay system that provides a quantitative tear protein analysis.

PHQ-9 yielded a mean score of 11.3±8.1 (0 to 27 possible), and PCL-M at 45.2±20.1 (range 17 to 85). Depression and PTSD-related anxiety were significantly correlated (r=0.82, P <.005). Regarding links with inflammatory markers; PHQ-9 results displayed a positive correlation with intercellular adhesion molecule 1, as did PCL-M (both r=0.36, P =.03). Similar relationships emerged between interleukin 8 (IL-8) and both subjective instruments (r=0.38, P =.02).

The presenters added that depression can be positively correlated (all r ~0.35) with other molecules: macrophage inflammatory protein-1 (MIP-1) α, MIP-1 β, IL-1 ɑ, and IL-1 β. In multivariable analysis including Schirmer-detected wetting length, demographic factors, and the 23 inflammatory markers tested, association between depression and MIP-1 ɑ persisted, as well as anxiety with IL-8.

“Past research has linked higher serum levels of these inflammatory markers to depression and anxiety; thus, tear biomarkers may be a less-invasive analysis tool,” according to the presentation.

This article originally appeared on Ophthalmology Advisor