Changes in regional cerebral blood flow on recovery from depression.

We have previously described focal abnormalities of regional cerebral blood flow (rCBF) in the left dorsolateral prefrontal cortex (DLPFC), anterior cingulate cortex and angular gyrus in 40 patients with major depression. We now report on the patterns of change in rCBF in a subgroup of 25 of the same patients who were rescanned following clinical remission of depression. Fifteen patients were scanned when optimally matched for drug treatment (4) or drug free on both occasions (11). The other 10 patients were fully recovered but could not be matched for drug status for clinical and ethical reasons. In a paired comparison of the same patients when ill and following recovery it was evident that remission was associated with a significant increase in rCBF in the left DLPFC and medial prefrontal cortex including anterior cingulate. Increases in rCBF in the angular gyrus were not seen when the comparison of depressed and recovered scans was matched for medication. The previously described relationship between clinical symptoms and brain perfusion in the depressed state was no longer present in the recovered state; this supports the hypothesis of state relatedness. Thus, recovery from depression is associated with increases in rCBF in the same areas in which focal decreases in rCBF are described in the depressed state in comparison with normal controls.