Executive deficits in major depression.

Clinically depressed patients and control subjects were examined by means of different tests to assess executive functions (the Wisconsin Card Sorting Test, the Stroop Color Word Test and a test of verbal fluency). The results indicate that the depressed patients were generally slower than the controls, as reflected by longer retrieval times for both words and colours. Furthermore, the depressed patients showed impairment with regard to altering behaviour appropriately in response to feedback. However, there were no depression-related increases in perseverative responses, and the ability to inhibit irrelevant information was unaffected by depression. No relationship was found between specific depressive symptoms or the severity of depression and cognitive performance. The overall pattern of results suggests that depression may affect various executive functions in a differentiated manner.