Attention bias for paranoia-relevant visual stimuli in schizophrenia

A number of studies indicate that patients with schizophrenia share a bias for paranoia-relevant material. The presence of an attentional bias for such stimuli would be of utter importance for our pathogenetic understanding of the disorder in view of ample evidence that patients with schizophrenia gather little information before arriving at strong conclusions: A both scarce and affectively biased data selection of available information may heavily distort its inner representation and thus prompt the formation of false beliefs. To date, the profile of this putative attentional bias in schizophrenia (e.g., automatic vs. controlled; hypervigilance towards vs. problems to disengage from such stimuli) is not fully uncovered.

To shed light on this aspect of information processing in schizophrenia, we administered a novel task based on the inhibition of return paradigm (IOR). Twenty-four schizophrenia patients and thirty-four healthy controls were presented neutral (e.g., cup), anxiety-relevant (e.g., shark), and paranoia-relevant cue pictures (e.g., gun) at either of two possible locations. Subsequent to either a short or long interval, a target appeared at the same or opposite location. Participants were requested to press a spatially corresponding button.

Both currently paranoid and nonparanoid schizophrenia patients responded faster to all kinds of targets following paranoia-relevant pictures, that is, such stimuli speeded reaction times irrespective of the cue-target interval and spatial correspondence.

This indicates that paranoia-relevant information generally alerts patients more than other stimuli and facilitates processing of subsequent information. Possible implications of this finding for our understanding of delusion formation and maintenance are outlined.