Frontostriatal deficits in unipolar major depression

Recent accounts of major depression have tended to focus on dysfunction of frontothalamic-striatal reentrant circuits as a possible source of the diso rder. Evidence of frontostriatal involvement in unipolar major depression f rom lesion and neuropsychological studies, and functional and structural im aging studies is examined. The high incidence of depressive symptomatology following left frontal and basal ganglia lesions implicate these as possibl e sites of dysfunction. Neuropsychological evidence indicates similar defic its in patients with major depression, perhaps with dorsolateral prefrontal deficits most prominent. Structural imaging studies report frontal and bas al ganglia (BG) abnormalities particularly in cases of late-age onset depre ssion. Resting state functional imaging studies show deficits in dorsolater al, anterior cingulate (medial frontal), and BG structures. Activation imag ing studies show less consistent evidence of dorsolateral deficit, while an terior cingulate deficit is more consistently demonstrated. Variability in findings across studies may reflect differences between subtypes of depress ion and differences in methodology. Possible involvement of the BG in the p sychomotor retardation of depression is examined. It is concluded that, whi le there is evidence of frontostriatal deficit in major depression, the exa ct nature of such deficits is uncertain. Issues such as component vs, syste m dysfunction need to be addressed. (C) 1998 Elsevier Science Inc.