Frontal EEG asymmetry as a promising marker of depression vulnerability: summary and methodological considerations

•Frontal EEG asymmetry may serve as a biomarker of depression risk.•It can predict future negative affect and potentially predict treatment response.•It may better index risk when recorded in emotionally evocative tasks than at rest.•A current source density transformation provides a promising index of depressive risk.•Simultaneous EEG-fMRI links frontal EEG asymmetry to neural systems connoting risk.

Frontal EEG asymmetry is a promising neurophysiological marker of depression risk. It predicts emotional response and negative affect hours to years later. Yet, inconsistencies in the literature may be due to differing methodological approaches between research groups. Within the past two years, a number of studies have shown this line of research may be strengthened by augmenting resting assessments with emotionally evocative tasks, utilizing optimal recording montages, and taking an integrative neuroscience approach that links frontal asymmetry to other indices of neural function. This review will focus on recent work in frontal asymmetry and depression with a particular focus on promising future directions and methodological considerations that may increase consistency between research groups.