Are early stages of visual information processing in schizophrenic patients disturbed? Results of an experimental study

In a study of early stages of visual information processing in schizophrenic patients, twenty acute schizophrenics, twenty remitted schizophrenics and twenty chronic schizophrenics were compared with control groups consisting of twenty healthy subjects and twenty depressive patients (psychiatric controls). The groups tested were matched for age, sex, and educational level. The psychiatric groups were selected according to the research diagnostic criteria (RDC) of Spitzer et al. Performance in a picture integration task and a backward masking task were measured. Chronic and acute schizophrenics showed similarly poor performance in the masking task compared to both control groups. The remitted schizophrenics, however, did not differ from the healthy controls or from the psychiatric controls. This finding contradicts the claim recently made by Merritt et al., that poor performance in backward masking is a trait marker for schizophrenia.