Automatic and effortful information processing in unipolar major depression.

The present study investigated attentional dysfunction in patients with recurrent unipolar major depression in a visual search paradigm. The attentional aspects of automatic and effortful information processing were examined. The general hypothesis was that patients with unipolar major depression would have more problems with tasks that require effortful information processing than with tasks that require only automatic information processing. A task requiring effortful processing attracts attention, is more demanding, and is instruction-driven. A task that is automatically processed does not invoke attention, is less demanding, and is stimulus-driven. The results showed that the patient group needed significantly longer reaction times on the tasks requiring more effortful information processing than the control group, but there were no significant differences between groups on tasks requiring automatic information processing. Thus it seems as if the depressed patients show an impaired profile as a function of the degree of effort a task requires.