Atypical depression: Enhanced right hemispheric dominance for perceiving emotional chimeric faces.

Abstract

Two studies compared hemispatial bias for perceiving chimeric faces in patients having either atypical or typical depression and healthy controls. A total of 245 patients having major depressive disorder (MDD) or dysthymia (164 with atypical features) and 115 controls were tested on the Chimeric Faces Test. Atypical depression differed from typical depression and controls in showing abnormally large right hemisphere bias. This was present in patients having either MDD or dysthymia and was not related to anxiety, physical anhedonia, or vegetative symptoms. In contrast, patients having MDD with melancholia showed essentially no right hemisphere bias. This is further evidence that atypical depression is a biologically distinct subtype and underscores the importance of this diagnostic distinction for neurophysiologic studies.

Grandchildren at High and Low Risk for Depression Differ in EEG Measures of Regional Brain Asymmetry

“…Depressed patients who respond favorably to a selective serotonin reuptake inhibitor (SSRI) show evidence of less right than left hemisphere activity, whereas treatment nonresponders show the opposite asymmetry (Bruder et al 2001;Bruder et al 2004;Sedoruk et al 2005). Reduced right hemisphere advantage for perceiving dichotic tones or emotional chimeric faces was found in patients having a MDD with melancholia but not in atypical depression (Bruder et al 1989;Bruder et al 2002). Although there is evidence for its clinical plausibility, less is known concerning the biological basis of parietal asymmetry.…”

Do age of onset and course of illness define biologically distinct groups within atypical depression?

“…That both groups' perceptual asymmetry differed significantly from healthy controls, but in opposite directions, seems most consistent with the two groups having different abnormalities in perceptual processing, rather than lying on a continuum from normal to abnormal. Further, the later onset or nonchronic patients share course of illness (i.e., later onset, Parker et al, 2001; and less chronic course, Kendler et al, 1996), treatment response (i.e., relatively high likelihood of responding to tricyclic antidepressants: Bielski & Friedel, 1976;Joyce & Paykel, 1989), and perceptual asymmetry (i.e., relative favoring of left-over right-hemisphere auditory processing: Bruder et al, 1989Bruder et al, , 2002 with melancholic patients, whereas the early onset, chronic atypical group differs from both melancholic patients and the later onset, nonchronic group on all of these dimensions. Thus, the later onset or nonchronic patients with atypical depression appear to have more in common with melancholic patients than with early onset, very chronic patients with atypical depression.…”

DSM-IV Depression with Atypical Features: Is It Valid?

“…All studies compared depressed patients having atypical features with other depressed patients, five including an undifferentiated group having neither melancholic nor atypical features. In all four studies that included patients with melancholic illness, those with atypical features differed (McGinn et al, 1996;Fountoulakis et al, 2004;Bruder et al, 2002;Joyce et al, 2002). In all five studies including an undifferentiated group, those with atypical features differed (McGinn et al, 1996;Anisman et al, 1999;Fountoulakis et al, 2004;Bruder et al, 2002;Joyce et al, 2002).…”

“…Unless atypical depression is differentiated from depressed patients with neither melancholic nor atypical features, applying atypical criteria could be a cumbersome way of saying melancholia is not present. McGinn et al (1996), Anisman et al (1999), Fountoulakis et al (2004), Bruder et al (2002, Stewart et al (1998), andJoyce et al (2002), partially answered the challenge of Parker et al (2002) (see Table 6). All studies compared depressed patients having atypical features with other depressed patients, five including an undifferentiated group having neither melancholic nor atypical features.…”

“…A weakness is that the controls are not further described. Bruder et al (2002) assessed chimeric faces as a measure of perceptual asymmetry. A chimeric face consists of fusion of a neutral right half-face with a smiling left half-face.…”