Arousal to aversive stimuli decreased in schizophrenia patients
MedWire News: Schizophrenia patients have reduced arousal when viewing aversive pictures compared with bipolar disorder (BD) patients and mentally healthy individuals, researchers have found.
"Both schizophrenia and BD are associated with disturbances in emotion processing," explain Sofie Aminoff (University of Oslo, Norway) and team in the journal Psychiatry Research.
They add: "Studying emotion processing across schizophrenia and BD offers a potential for identifying shared and illness-specific allied phenotypes in these disorders. However, to our knowledge no previous study has investigated the differences and similarities in emotional processing between healthy controls, BD, and schizophrenia."
To address this, the team recruited 102 patients with schizophrenia, 110 with BD, and 135 mentally healthy controls aged 18-65 years.
The participants were asked to view 72 pictures from the International Affective Picture System designed to elicit negative (aversive) or neutral emotions. Within the aversive picture set, 18 of the 36 pictures had social/interpersonal content while none of the 36 neutral pictures had social/interpersonal content.
For each of the pictures, the participants were required to evaluate subjective valence (pleasant-unpleasant) and arousal (low-to-high) on a nine point likert-type scale.
The researchers found that there were no significant differences in valence ratings for aversive or neutral pictures among the three groups. There were also no significant differences in arousal ratings for aversive or neutral pictures between BD patients and controls.
However, patients with schizophrenia had significantly lower arousal ratings for aversive pictures with a social/interpersonal content than BD patients and controls, at 5.0 versus 5.6 and 6.1, respectively. They also had lower arousal ratings for aversive pictures without a social/interpersonal content, at 4.4 versus 5.0 and 5.1, respectively.
This difference was more pronounced in women than men with schizophrenia, the researchers note.
Aminoff and team conclude: "The current findings support the hypothesis of a disorder-specific disturbance in response to aversive visual stimuli in schizophrenia that appear more pronounced for social aversive pictures and for females.
"This adds to the notion that impaired emotion processing is an important feature of schizophrenia."
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By Mark Cowen