Investigation of Retinal Biomarkers in Adult ADHD: A Comparative Optical Coherence Tomography Study

Attention-deficit/hyperactivity disorder (ADHD) is increasingly recognized as a condition with both neurodevelopmental and neurodegenerative components. This study aims to investigate retinal structural alterations in adults diagnosed with ADHD using optical coherence tomography (OCT) and to identify potential retinal biomarkers.

The study included 31 adults diagnosed with ADHD according to DSM-5 criteria and 33 age- and sex-matched healthy controls. Retinal measurements were obtained from the right eye of all participants using the Spektralis® OCT system in accordance with the ETDRS protocol. Retinal nerve fiber layer (RNFL), ganglion cell layer (GCL), inner plexiform layer (IPL), ganglion cell complex (GCC), and central macular thickness (CMT) were measured. ADHD symptom severity was assessed using the Adult ADHD Self-Report Scale (ASRS). Group comparisons were made using independent t-tests, and correlations with clinical measures were evaluated using Pearson correlation analysis.

Compared to healthy controls, the ADHD group showed a statistically significant thinning in the CMT, IPL, and GCC layers, especially at the 1 mm zone (p < 0.05).

CMT (254.3 µm vs. 268.7 µm), IPL (35.2 µm vs. 38.4 µm), and GCC (78.5 µm vs. 82.3 µm). Similar thinning patterns were observed at the 3 mm zone for CMT and GCC, and at the 6 mm zone for IPL. No statistically significant differences were found in RNFL and GCL measurements. Thinning in specific retinal layers was significantly correlated with higher ADHD severity scores.

Our study demonstrates that adults with ADHD exhibit measurable retinal thinning, particularly in the CMT, IPL, and GCC layers. These structural changes may reflect underlying neurodegenerative processes and suggest that retinal imaging via OCT could serve as a useful non-invasive biomarker in adult ADHD.