Sex-dominant differences in resting-state EEG microstates among young adults at risk of smartphone addiction

Background Smartphone addiction (SA) is increasing, but sex-sensitive neurophysiological markers for assessment and follow-up remain limited. Methods In a balanced 2 × 2 design (sex × group; N = 120), young adults had resting-state EEG. Microstates A–D were extracted from GFP peaks using polarity-insensitive k-means ( k = 4). Individual metrics (mean duration, occurrence, coverage, GEV) were compared using two-way ANOVA with FDR control ( q = 0.05). Results Sex effects outperformed group effects. Females had higher microstate C metrics—duration: F (1, 116) = 12.84, p = 0.001, ηp 2 = 0.100; coverage: F (1, 116) = 14.21, p < 0.001, ηp 2 = 0.109; occurrence: F (1, 116) = 9.02, p = 0.003, ηp 2 = 0.072, while males had higher microstate D metrics—coverage: F (1, 116) = 7.01, p = 0.009, ηp 2 = 0.057; occurrence: F (1, 116) = 16.82, p < 0.001, ηp 2 = 0.127; duration did not differ ( p > 0.05). These patterns remained FDR-significant at q = 0.05. Conclusion Resting EEG microstates reveal sex-dominant dynamics associated with salience (C) and dorsal attention (D) processes in SA with high impulsivity, indicating the need for sex-sensitive screening and follow-up in addition to questionnaires.