Changes in regional brain activity in major depression after successful treatment with antidepressant drugs

Relative regional cerebral blood flow was measured with single photon emission computed tomography (SPECT) using 99m Tc-hexamethyl-propyleneamine oxime ( 99m Tc-HMPAO) in 16 patients with major depression while they were in the depressed state as well as in remission. All patients were closely matched with regard to medication status. In the depressed state, significant reductions in tracer uptake were found in the left superior frontal, bilateral parietal and right lateral temporal cortex. During remission, significant increases in uptake were found in the left superior frontal, right parietal and right lateral temporal cortex. There were no significant differences in tracer uptake between patients in remission and controls. These findings suggest that the regional decreases in tracer uptake observed in the depressed state might be a state-related abnormality.