Objectives. Depression is a frequent feature of schizophrenia but the cognitive processes involved in its development and maintenance are unclear. Recent studies have shown that clinical depression is associated with faulty inhibitory mechanisms of selective attention for negative information. The current study examined whether patients with schizophrenia also have an attentional bias towards negative stimuli. The inhibitory processes of interference control and task-shifting abilities were also examined to assess whether patients would show a selective impairment.
Method. Forty-three patients with schizophrenia and 24 healthy controls completed the Affective Shifting Task.
Results. As a group, schizophrenia patients did not show an attentional bias for negative material. However, those patients with high levels of depression demonstrated faster latencies when negative words were the targets, and higher depression scores were found to be associated with an increasing number of false alarms for negative words when they were not the targets. The results also showed that patients had impaired interference control but intact task-shifting abilities.
Conclusions. Faulty inhibitory mechanisms of selective attention for negative information are not a general feature of schizophrenia but appear to be selective to those with a depressed mood. The results highlight the need for further studies examining the exact nature of the affective dysfunction in schizophrenia and the cognitive processes supporting negative emotions.