Cognitive deficits in depression: Possible implications for functional neuropathology

BACKGROUND: While depression is known to involve a disturbance of mood, movement and cognition, its associated cognitive deficits are frequently viewed as simple epiphenomena of the disorder. AIMS: To review the status of cognitive deficits in depression and their putative neurobiological underpinnings. METHOD: Selective computerised review of the literature examining cognitive deficits in depression and their brain correlates. RESULTS: Recent studies report both mnemonic deficits and the presence of executive impairment--possibly selective for set-shifting tasks--in depression. Many studies suggest that these occur independent of age, depression severity and subtype, task 'difficulty', motivation and response bias: some persist upon clinical 'recovery'. CONCLUSIONS: Mnemonic and executive deficits do no appear to be epiphenomena of depressive disorder. A focus on the interactions between motivation, affect and cognitive function may allow greater understanding of the interplay between key aspects of the dorsal and ventral aspects of the prefrontal cortex in depression.