Background. Cognitive theories of persecutory delusions in schizophrenia include increased
attention to threat and reduced re-appraisal of information during decision-making.Methods. We employed visual scan path measurements, an ‘on-line’ marker of attention, in
schizophrenic patients with persecutory delusions (N = 19), negative symptom- and medication-matched patients with non-persecutory delusions (N = 8), and normal controls (N = 18). Stimuli
comprised black-and-white photographs of social scenes rated as depicting either neutral,
ambiguous or overtly threatening activity. Foreground areas containing salient information with
regard to the overall scene were rated independently as either threatening or non-threatening in both
the overtly threatening and ambiguous scenes; all foreground areas were rated as non-threatening
in the neutral scene.Results. For the ambiguous scene only, schizophrenics with persecutory delusions directed gaze to
less threatening areas, and, for all three scenes, demonstrated reduced re-appraisal of information
compared with both control groups. All subjects showed similar viewing strategies for the overtly
threatening and neutral scenes.Conclusions. These findings suggest abnormal information gathering and evaluation in schizophrenics,
specifically related to the presence of persecutory delusions. In particular, the results point
to biased processing of contextual information in an ambiguous setting in these patients, and
perhaps perception of threat in inappropriate places.
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