Symptom correlates of vulnerability to backward masking in schizophrenia.

The authors used the backward-masking procedure to investigate visual information processing in schizophrenic and bipolar patients, determining the critical interstimulus interval at which the masked target could be identified for each subject. Multiple regression analysis revealed that a negative symptom rating was a significant predictor of this interval among schizophrenic patients: greater negative symptoms were associated with longer intervals. Positive symptom ratings were not predictive of performance. Symptom ratings did not predict performance of bipolar patients. Group comparisons revealed that schizophrenic patients who had mixed positive and negative symptoms had significantly longer intervals than normal control subjects did. These results have implications for theories of information processing in schizophrenia.