Electrophysiological indicators of inhibitory control deficits in depression

•Examined inhibitory control deficits in MDD using ERPs measured during SSRT task.•MDD participants did not show differences in P300 amplitude during SSTs vs. USSTs.•dP300 was modulated by level of depressive symptoms and reflective pondering.•Depression is associated with impaired conflict resolution. Ample evidence from behavioral and brain imaging studies suggests that inhibitory control is impaired in depression, though the precise nature of this impairment is unclear. The purpose of the present study was to examine potential deficits in three aspects of inhibitory control – conflict monitoring, conflict resolution, and overt behavioral inhibition – in the context of depressive symptoms. Depressed (n=15) and non-depressed (n=15) participants completed a stop-signal reaction time (SSRT) task while electroencephalography (EEG) data were recorded. EEG results indicate that depression impacts only the conflict resolution phase of inhibitory control, with higher levels of depressive and reflective pondering symptoms associated with poorer conflict resolution. Findings have clear implications for treatments of depression, many of which do not currently target the inhibitory control deficits present in this disorder.