Affective modulation of external misattribution bias in source monitoring in schizophrenia

Background. Schizophrenic patients tend to attribute internal events to external agents, a bias that may be linked to positive symptoms. We investigated the effect of emotional valence oil the cognitive bias. Method. Male schizophrenic subjects (n = 30) and an experimenter alternatively produced neutral and negative words. The subject then decided whether he or the experimenter had generated the item. Results. External misattributions were more common than self-misattributions, and the bias was greater for patients with active hallucinations and delusions relative to patients in remission. Actively psychotic patients but not patients in remission were more likely to generate external misattributions with negative relative to neutral words. Conclusions. Affective modulation of the externalizing cognitive bias in source monitoring is evident in patients with hallucinations and delusions.