Neurocognition in depression: patients on and off medication versus healthy comparison subjects

Abstract

Patients with depression have neuropsychological deficits in attention, memory, psychomotor speed, processing speed, and executive function. It is not clear, however, whether neurocognition in depression is impaired in a global or nonspecific way or if specific cognitive domains are selectively impaired. This naturalistic cross-sectional study employed a computerized neurocognitive screening battery to evaluate 38 depressed, drug-free patients, compared to 31 patients who responded to antidepressant monotherapy and to 69 healthy comparison subjects. There was evidence for global neuropsychological impairment in untreated depressed patients. In patients who had been successfully treated, performance was improved but not normalized. There was also evidence for specific depression-related deficits in executive function and processing speed but not in memory, psychomotor speed, or reaction time. Although depressed patients have global neurocognitive impairments, deficits in certain cognitive domains are more important than in others. In particular, impairments are noted in tests of executive control and in tests that demand effortful attention. Information processing speed is also impaired but not reaction time. Computerized testing in the clinic setting demonstrates a range of neurocognitive problems in patients with depression. These problems may have a bearing on treatment and outcome.