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Depression is one of the most serious psychiatric diseases of the 21st century. This chronic illness causes severe reductions in quality of life of affected individuals and significant costs for health systems worldwide. Besides anhedonia, sad mood, and reduction of drive, most patients suffering from depression also report a lack of concentration and diminished decision- making ability. In particular, previous work has demonstrated that depression is associated with deficits of executive functions. Several experimental designs have been developed to test for executive functioning, especially the Kopp-Flanker and the GoNogo-Paradigm. Brain imaging studies that applied these paradigms in fMRI-settings provided evidence for specific neural correlates of impaired executive functioning. In these studies, the anterior cingulate and the prefrontal cortex seem to be impaired, especially in depressed individuals. By means of event- related potentials, neurophysiological investigations, too, have indicated that depressed individuals have deficits in executive functioning. However, ERP-findings are not consistent so far. Importantly, there is also evidence for a link between certain personality traits and depressiveness. However, so far, only very little is known about this potentially crucial connection and further work is needed. In the current study, the indicated relation between brain function, depression and personality was investigated. A group of 24 depressed individuals and 24 non-depressed control participants were tested on a Kopp-Flanker-paradigm targeting their executive functioning while EEG was recorded. To measure the subject’s self-regulation capability, the “Selbststeuerungsinventar” according to Kuhl and Fuhrmann was applied. The results showed no group differences in reaction time but elevated error rates in the group of depressed patients. Furthermore, a reduced P3 component was observed in the depressed group, while the N2 component seemed to be unaffected. Crucially, however, the current study provides evidence that a specific dimension of a person's self-regulation capability, namely, the feeling for one's self, mediates the relation between depression and brain function.