Systemic inflammation correlates with QEEG abnormalities in drug-naïve schizophrenia patients

Previous studies have demonstrated increased inflammatory markers and altered quantitative electroencephalography (qEEG) findings in schizophrenia. This study explores the relationship between systemic inflammation and electrophysiological changes in drug-naïve first-episode schizophrenia to understand the disorder's etiopathogenesis better. Eighty-two patients with first-episode schizophrenia (DSM-5) and 62 healthy, age- and sex-matched controls were included. Absolute spectral power (ASP) of frequency bands and slow-to-fast frequency ratios were analyzed using qEEG. Inflammatory markers, including the neutrophil-to-lymphocyte ratio (NLR), monocyte-to-lymphocyte ratio (MLR), and neutrophil-to-albumin ratio (NAR), were measured and correlated with qEEG indices. Inflammatory markers such as neutrophil count, NLR, MLR, and NAR were significantly elevated in patients. Theta wave power increased globally, delta wave power was higher in parietal and occipital regions, and alpha power was elevated in frontal, parietal, and central regions. Inflammatory markers were negatively correlated with theta power and theta/beta ratios, linking systemic inflammation to altered brain activity. These findings support the inflammatory hypothesis of schizophrenia and suggest that qEEG indices and inflammatory markers may serve as potential biomarkers. The negative correlation between inflammatory markers and theta wave power indicates that inflammation affects electrophysiological processes in schizophrenia. Larger multicenter studies are needed to confirm these results.