BACKGROUND The spontaneous diurnal variation of mood and other symptoms provides a substrate for the examination of the relationship between symptoms and regional brain activation in depression.
METHOD Twenty unipolar depressed patients with diurnal variation of mood were examined at 8 a.m. and 8 p.m. with neuropsychological measures, clinical ratings and single photon emission tomography (SPET). Brain perfusion maps were spatially transformed into standard stereotactic space and compared pixel-by-pixel. A parametric (correlational) analysis was used to examine the relationship between symptom severity and brain perfusion, both between and within subjects.
RESULTS Global depression severity and an independent 'vital' depression factor were associated in subjects with increased perfusion in cingulate and other paralimbic areas. In addition there was a probable association between an increase in an anxious-depression factor and reduced frontal neocortical perfusion.
CONCLUSIONS Depressive symptom changes are associated with metabolic changes in the cingulate gyrus and associated paralimbic structures.