Abstract
Depressive disorder results in significant functional impairment. Cognitive deficits are one of the causes of this disruption.
There is a lower degree of impaired cognition in depression than in dementia or psychotic disorders; however, it is not just a state marker, but also trait marker. Cognitive dysfunctions in major depression can be observed not just as consequence of depressive symptoms during acute episode, but also in remitted patients.
Impaired cognitive functioning has been found even in first-episode patients. Patients with depression have impairments of both "cold cognition" (emotion-independent: executive functions, attention, working memory, general and psychomotor processing speed) and "hot cognition" (emotion-laden: social misinterpretation, negative bias).
Cognitive deficits are often residual symptoms, significantly interfere with everyday functioning, contribute to functional impairments. Patients themselves subjectively perceive low cognitive performance; the primary instruments for objective detection and assessment are neuropsychological tests.
In clinical practice, these tests are not usually available, simple self-reported measures can be used instead. Both non-pharmacological (e.g., cognitive remediation) and pharmacological interventions are used for treatment of cognitive deficits in depression.
Preliminary data indicate that a combination of remediation and pharmacotherapy can be more efficacious than drugs alone. So far, there is a limited number of randomized trials with antidepressants, either placebo-controlled or head-to-head comparisons, primarily testing procognitive effects in non-geriatric depressed patients.
As for drug therapy, there is evidence that dual (duloxetine) and multimodal (vortioxetine) antidepressants are effective. Other agents (e.g., stimulants, cognitive drugs, hormones, glutamatergic antagonists, nutritional supplements) are being experimentally tested as adjuvant therapy.