Despite significant advances in the elucidating the neurobiology of depression in recent years, the neurobiological correlates of cognition also warrant further investigation. Since it is undisputed that psychological processes, including cognitive function, have a neuronal representation, several structural and functional alterations related to neuropsychological impairments in patients with mood disorders have been documented via neuroimaging (9). In addition to gray matter changes such as atrophy in the prefrontal cortex (PFC), the cingular cortex with prominent changes in the left subgenual cingular cortex (39), the temporal cortex, and the basal ganglia (39), white matter damage has also been documented (40). In particular, the effects of cortisol on brain structure has been suggested to be relevant in the etiology of MDD more generally and of cognitive impairment in depression in particular. Since pathological abnormalities of the hypothalamic-pituitary-adrenal axis (HPA) in conjunction with an increased excretion of cortisol in depression have been described, the abnormalities of the HPA axis following stress may lead, or at least contribute, to the structural changes such as those evident in the hippocampus. These findings are supported by
