Longitudinal rCBF Changes Measured with SPECT in Patients with Depression Undergoing Treatment

Regional cerebral blood flow (rCBF) studies of major depression have yielded variable results. The present study employed a longitudinal observation method to measure rCBF every 3 months during treatment. Thirteen patients with major depressive disorder underwent single-photon emission computed tomography (SPECT) with 99mTc-HMPAO three times over a 6-month period. rCBF was analyzed with the Statistical Parametric Mapping. The findings were compared to scans from 14 normal control subjects. Depression symptoms were rated using the Hamilton Rating Scale for Depression. At baseline, the main regions with lower rCBF compared to controls were the middle and inferior frontal gyri, superior temporal gyrus, and cingulate cortex. Three months later, despite significant improvement of depressive symptoms, decreased rCBF was observed in the same regions, but to lesser extent. At 6 months, depressive symptoms showed continued improvement, and rCBF in the superior temporal gyrus increased up to control levels, but rCBF in the temporal pole, cingulate, and inferior frontal gyrus remained low. The results of the present study suggest that there might be time- and state-dependent differences in rCBF recovery in patients with major depression.