Neural differentiation of anxiety: An EEG-based comparative study of panic disorder and major depressive disorder

Background: Panic disorder (PD) and major depressive disorder (MDD) frequently co-occur, leading to poorer prognosis. Although anxiety symptoms in both conditions appear similar, their underlying mechanisms may differ, as indicated by shared and distinct features in theoretical models and neurophysiological findings. This study investigates EEG-based neural differentiation of anxiety between PD and MDD, integrating the Tripartite Model and Five-Factor Structure. Methods: This retrospective study analyzed resting-state electroencephalographic (EEG) data from 75 participants (PD: n = 35; MDD: n = 40). Generalized estimating equations examined group differences in EEG absolute power (μV²) and asymmetry across frontal, central, and posterior regions. These differences were assessed in relation to factors associated with Anxious Arousal and Negative Affect from the Five-Factor Structure, measured via the Beck Depression Inventory (BDI) and Beck Anxiety Inventory (BAI), across five frequency bands (delta, theta, alpha, beta, gamma). Additional analyses explored subregional differences in temporal, parietal, and occipital areas. Results: While Anxious Arousal showed no distinct neural patterns, Negative Affect revealed significant group differences in posterior beta-band asymmetry. In the posterior temporal region, the PD group exhibited increased rightward asymmetry, whereas the MDD group showed decreased rightward asymmetry. Significant group differences in posterior parietal asymmetry were also observed for Negative Affect, but these contrasting trends were not significant. Conclusions: The distinct neurophysiological patterns for Negative Affect observed between PD and MDD may serve as potential neurobiological markers and support the exploration of treatment neuromodulation strategies targeting specific neural circuits, particularly in posterior brain regions, to alleviate anxiety symptoms.