Using single photon emission computed tomography (SPECT) brain imaging with the HMPAO Tc-99m perfusion technique, Rie measured the variations of HMPAO uptake ratios before and after 5 weeks treatement in 26 unipolar depressive patients meeting the diagnostic criteria of major depressive disorder according to the DSMIII-r. The aim of this study was to compare for these patients changes in brain HMPAO uptake according to antidepressant responsivness in major depression. After the second assessment, they were divided in 3 groups according to clinical improvment rated with MADRS and BECK : group A, n = 8 good response (MADRS and BECK < 8); group B, n = 9 partial response (9 < MADRS and BECK < 14); group C, n = 9 unsatisfying response (MADRS and BECK > 15). Between two exams, the data analysis showed increase HMPAO fixation ratio, in anterior cerebral regions in group A, in median and posterior regions in groupe B. No variation HMPAO uptake was noted in group C. Initial measures of HMPAO uptake indexes in right lateral frontal and occipital regions and variation indexes after treatment permitted to differentiate group. Regarding prognosis preoccupations, pre-treatment SPECT pattern may also be useful to consider treatement responsiveness.