Changes in regional cerebral perfusion in depression. Monitoring treatmentresponse with SPECT

The objective of this study was to investigate the relationship between the effect of sleep deprivation, recovery and regional brain perfusion in pati ents with major depression. Regional cerebral blood flow was assessed by 99 mTc-HMPAO-SPECT before and after sleep deprivation in fourteen medicated pa tients. Three of the patients underwent a follow-up measurement after clini cal recovery and with an unchanged antidepressant medication. Before sleep deprivation the responding patients had a significantly higher anterior cin gulate perfusion than the nonresponding patients, that normalized after sle ep deprivation. Cingulate perfusion uniquely differentiated eventual treatm ent response from non-responders, as perfusion in no other region under stu dy discriminated the two groups. At baseline all patients revealed hypoperf usion in the left prefrontal cortex when compared to the right side, which was not affected by sleep deprivation, whereas prefrontal hypoperfusion was reversible upon remission. These findings are in agreement with previous P ET investigations and provide evidence for cingulate and prefrontal dysfunc tion associated with depression, that are reversible by successful treatmen t and may represent state markers.