Resting frontal brain asymmetry is linked to future depressive symptoms in women.

This longitudinal pilot study examined whether baseline resting frontal electroencephalographic (EEG) asymmetry correlates with depressive symptoms during the most impaired two-week period in the following year. Current-source-density (CSD) transformed resting frontal EEG asymmetry, severity of depression symptoms (Beck Depression Inventory - II), and stress (indexed by negative life events; NLE) were recorded in never-depressed young adults with no current DSM-IV diagnosis (38 women, 16 men) at baseline. One year later, depression symptoms and NLEs experienced during the interim were assessed. Individuals who reported greater interim NLEs also endorsed interim higher depression symptoms, a pattern that replicated when first accounting for baseline stress and depression. For women, higher depression reported at follow-up was linked to lower left than right frontal EEG activity at baseline, a pattern that replicated when first accounting for depressive symptoms at baseline. Despite the modest sample size of the present analysis, findings are consistent with prior reports of sex differences in patterns of brain laterality and support the idea that CSD-referenced EEG asymmetry may be a risk marker for future depression in previously healthy young women.