Neuropsychological deficits in depressive disorders

Neuropsychological deficits are considered a significant feature of depression both for their differential value in the diagnostics and the underlying pathophysiology of depressive disorders. The studies reviewed in the present paper predominantly focus on memory disorders as well as frontal-lobe associated dysfunctions such as deficits of attentional performance and executive functions. Despite heterogenous results in the literature, there is emerging evidence that executive functions and anterograde memory performance are those domains predominantly affected in depressive disorders. The fact that not all depressive patients display neuropsychological deficits rather indicates a dominant role of moderating variables. We discuss the following variables possibly intervening with type and degree of neuropsychological dysfunction: [1] severity and remission of depressive disorders, [2] age of patients and age at the first manifestation of a depressive disorder, [3] psychological factors such as motivation and coping with failure, [4] type and efficacy of antidepressive drug treatment, [5] duration of the stay as inpatients, [6] number of depressive episodes, and [7] gender. Furthermore, we discuss the theory of a dysfunction of fronto-striatal circuits as an underlying mechanism of depressive disorders. The majority of neuropsychological findings seem to support this theory.