Differential responses to emotional interference in paranoid schizophrenia and bipolar mania

Background: Studies on emotional biases towards threat-related stimuli in schizophrenia and bipolar disorder have provided, so far, inconsistent results. The aim of the present study was to investigate emotional interference in acute schizophrenic and manic patients and its clinical correlates by using a card version of the Emotional Stroop Task designed with neutral, paranoid, depressive and manic words.

Methods: Thirty paranoid schizophrenia patients, 30 manic patients and 60 healthy controls were compared on the Emotional Stroop Test. Response times (RT) were collected for each card. Interference indices were calculated by subtracting the RT for the neutral card from the RT for the depressive, paranoid and manic cards.

Results: The schizophrenic and manic patient groups showed an increased interference effect when the emotional valence was relating to the disorder-specific psychopathology. In addition, the paranoid interference index correlated with positive symptoms in schizophrenic patients. By contrast, no correlation was evidenced between interference indices and mood symptoms in the manic group.

Conclusions: Among schizophrenic patients, paranoid interference might be a state-related emotional abnormality associated with persecutory delusions. In mania, we suggest that emotional biases towards depressive as well as manic information might be trait features of the emotional hyperreactivity involved in the vulnerability to bipolar disorder.