title: The perception of emotional chimeric faces in patients with depression, mania and unilateral brain damage.
abstract: BACKGROUND
  Judgements made on chimeric faces elicit reliably a perceptual bias to the left hemispace, presumed to be due to right hemisphere dominance for emotional processes. Major depressive illness has been shown to attenuate this bias. The aim of this work was to examine lateral perceptual bias in bipolar I and II patients in a hypomanic state and unipolar depressed patients and those with unilateral hemisphere damage following stroke.
  
  
  METHODS
  Sixty patients with DSM-IV affective disorder (30 bipolar I or II, currently hypomanic, 30 unipolar depressives), 30 right brain-damaged patients, 30 left brain-damaged patients and 30 healthy controls were given the Happy-Sad Chimeric Faces Test.
  
  
  RESULTS
  Right hemisphere damaged and unipolar depressed patients both showed a significantly reduced left hemispatial bias (LHB) compared to controls, bipolars and left brain-damaged patients. No significant difference in mean LHB between controls and both hypomanics and left brain-damaged patients was found. There was no significant association between LHB and clinical variables.
  
  
  CONCLUSIONS
  The results suggest a physiological distinction between bipolar and unipolar depression. The significantly diminished left hemifacial bias in depressed patients suggests right hemisphere dysfunction.
authors.affiliation: Section of Cognitive Neuropsychiatry, Department of Psychological Medicine, Institute of Psychiatry, London.
authors.forename: Katarzyna
authors.initials: K
authors.lastname: Kucharska-Pietura
authors.forename: Anthony S
authors.initials: AS
authors.lastname: David
mesh_terms: D000368:Aged; D001714:Bipolar Disorder / Q000503:physiopathology / Q000523:psychology; D001930:Brain Injuries / Q000503:physiopathology / Q000523:psychology*; D003866:Depressive Disorder / Q000503:physiopathology / Q000523:psychology; D004644:Emotions; D005149:Facial Expression; D005260:Female; D007839:Functional Laterality; D006801:Humans; D008297:Male; D008875:Middle Aged; D019964:Mood Disorders / Q000503:physiopathology / Q000523:psychology*; D009483:Neuropsychological Tests; D010364:Pattern Recognition, Visual