INCREASED LIMBIC BLOOD-FLOW AND TOTAL SLEEP-DEPRIVATION IN MAJOR DEPRESSION WITH MELANCHOLIA

Single photon emission computed tomography (SPECT) with technetium-99m -d,l-hexamethyl-propylene amine oxime (99Tcm-HMPAO) was carried out in 20 melancholic patients before and after total sleep deprivation. Fin dings in 11 responders to total sleep deprivation (defined by greater than or equal to 40% improvement on the Hamilton Rating Scale for Depr ession) were compared with findings in nine nonresponders. On the basi s of a semiquantitative evaluation of SPECT findings, responders showe d relative hyperperfusion before sleep deprivation in the right anteri or cingulate cortex and in the right and left frontoorbital cortex and basal cingulate gyrus. Responders who showed greater than or equal to 50% improvement also showed hippocampal overactivation before sleep d eprivation. It is possible that limbic overactivation may characterize depressed responders to total sleep deprivation as a distinct subtype . Another possibility is that the pattern of limbic hyperactivation re flects the increased number of bipolar patients in the responder group , with response to total sleep deprivation being only a covariate of t his bipolar-unipolar distinction.