P3 reductions in depression have been reported using a challenging dichotic listening test (Bruder et al., 1995), and a dichotic oddball task (Tenke et al., 2008). However, reports of reductions in simpler oddball tasks have been inconsistent (for reviews, see Bruder, Kayser, & Tenke, in press Roth, Duncan, Pfefferbaum, & Timsit-Berthier, 1986), and may be dependent on patients’ clinical characteristics. In a binaural oddball task, Bruder et al. (2002) reported an early P3 factor (nose reference; 315 ms peak latency), having a topography that included midline frontocentral sites, which was separable from a later P3 (400 ms) subcomponent, with a parietal topography typical of P3b. The former factor was larger in patients having an anxiety disorder alone when compared to depressed patients or healthy controls. Patients having depressive disorder with comorbid anxiety disorder, but not depression alone, tended to have a smaller early P3 than healthy controls. In contrast, the late P3 was larger in depressed patients having a comorbid anxiety disorder when compared to the other groups, but did not differ between patients having a depressive disorder alone and
