Detection of facial expressions of emotions in schizophrenia.

The aim of the present study was to examine spatial processing of facial emotion in schizophrenic patients suffering from affective symptoms. A face-in-the-crowd task using schematic stimuli was administered to schizophrenic patients with flat affect (n=30), schizophrenic patients suffering from anhedonia (n=30), schizophrenic patients not suffering from anhedonia or flat affect (n=28), and a group of healthy controls (n=30). Participants searched displays of neutral schematic faces for a face with a positive or negative mouth expression. Schizophrenic patients manifested a general slowing of response speed compared to normal subjects. All patient groups as well as normal subjects found negative faces more quickly than positive faces amongst neutral faces. Unexpectedly, with increasing anhedonia as assessed by psychiatric rating, a more efficient spatial detection of positive facial expression was observed. For flat-affect patients only, efficiency of search for negative facial expression did not differ from that in the neutral face control condition. This response pattern indicates that, in flat-affect schizophrenic patients, spatial search of negative facial expression might be slowed after the initial engagement of search processes. Potential explanations of the face processing effects found in anhedonia are discussed.