Lateralization of facial emotional expression in schizophrenic and depressed patients

This study examined facial emotional expressions produced by schizophrenics (SZ), unipolar depressed (UD), and normal control (NC) right-handed adults. Hypotheses regarding right-hemisphere activation in UD and suppression in SZ were addressed, as well as hypotheses about emotion and laterality. Subjects were videotaped while posing positive, neutral, and negative facial expression to verbal command and to visual imitation. Naive judges rate hemiface stimuli for intensity in original and mirror-reversed orientations. Overall, SZs produced expressions with diminished intensity relative to UDs and NCs. Across subject groups, expressions were more intense in the visual than the verbal condition. In general, approach expressions were produced with greater right-hemiface intensity, and withdrawal expression with greater left-hemiface intensity. UDs showed more pronounced facial asymmetry than SZs or NCs. An unanticipated right-hemiface perceptual bias among the judges may reflect the analytical, detailed rating procedure used and the presumably greater reliance by the judges on left- than right-hemisphere strategies.