General visual processing deficits may underlie social difficulties in schizophrenia
MedWire News: Patients with schizophrenia respond more slowly and less appropriately to face, body, and car images than do healthy individuals, reports a German research team.
The researchers also found that schizophrenia patients have reduced inversion abilities, and say their findings are suggestive of impaired configural processing in such patients.
The difficulties in understanding and handling social interactions observed in schizophrenia patients appears to stem from an inability to derive relevant information from faces and physical appearances.
Observing that a schizophrenia patient's body perception may also be impaired, Patrizia Thoma, from Ruhr-University Bochum, and colleagues administered a series of basic face perception tests, including identity discrimination, memory for faces, and recognition of facial affect, to 17 patients with schizophrenia or schizoaffective disorder and 17 healthy controls.
The tests were supplemented with a matching-to-sample task that included emotional and neutral faces, bodies, and cars either in standard or inverted orientation, the team reports in the journal Psychiatry Research.
On the basic face perception tasks, schizophrenia patients performed worse in facial recognition and recognition memory than did healthy controls, and made more errors on affect naming and affect matching subtests.
Turning to the matching-to-sample results, the researchers found that patients had slower responses than controls, and had significantly longer reaction times to inverted relative to upright images. Further analysis indicated that patients had an overall significantly smaller inversion effect than controls.
In addition, patients had significantly fewer correct responses than controls, and fewer correct responses for inverted relative to upright pictures. Interestingly, the inversion effect among patients for bodies was significantly larger than that for cars. However, none of the findings were significantly correlated with either IQ or Positive and Negative Syndrome Scale symptom scores.
The researchers write: "Like healthy controls, patients with schizophrenia showed an inversion effect for human bodies indicating that both faces and bodies seem to be processed by similar mechanisms. However, in terms of response speed, the inversion effect was reduced in schizophrenia patients relative to controls across all categories."
"Overall, the data point towards reduced configural processing, not only for faces, but also for bodies and cars, in individuals with schizophrenia," they conclude.
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By Liam Davenport