Changes in regional cerebral blood flow during acute electroconvulsive therapy in patients with depression: positron emission tomographic study.

BACKGROUND Although electroconvulsive therapy (ECT) is widely used to treat psychiatric disorders such as depression, its precise neural mechanisms remain unknown. AIMS To investigate the time course of changes in cerebral blood flow during acute ECT. METHOD Cerebral blood flow was quantified serially prior to, during and after acute ECT in six patients with depression under anaesthesia using [(15)O]H(2)O positron emission tomography (PET). RESULTS Cerebral blood flow during ECT increased particularly in the basal ganglia, brain-stem, diencephalon, amygdala, vermis and the frontal, temporal and parietal cortices compared with that before ECT. The flow increased in the thalamus and decreased in the anterior cingulate and medial frontal cortex soon after ECT compared with that before ECT. CONCLUSIONS These results suggest a relationship between the centrencephalic system and seizure generalisation. Further, they suggest that some neural mechanisms of action of ECT are mediated via brain regions including the anterior cingulate and medial frontal cortex and thalamus.