Hemispheric asymmetry in depressive symptoms is associated with sex-divergent functional brain connectivity patterns

Hemispheric asymmetry has been linked to depressive symptoms, yet its relationship with large-scale brain network organization remains unclear. Resting-state electroencephalography (EEG) was recorded from 489 university students to examine hemispheric asymmetry associated with depressive symptoms and its relation to functional connectivity, with attention to sex-dependent patterns. Asymmetry indices and connectivity strength and density were computed across six frequency bands. Depressive symptoms were primarily associated with asymmetry alterations in the α and δ bands, most prominently in frontal α1 asymmetry. At the network level, elevated depressive symptoms were linked to reduced connectivity strength and density, particularly in the α2 and β1 bands, with significant sex × depressive symptom interactions. Alpha2-band connectivity statistically explained a proportion of the association between depressive symptoms and multiple asymmetry indices. These findings indicate that hemispheric asymmetry co-occurs with frequency- and sex-dependent variations in large-scale functional brain organization.