Background: This PET study is a continuing investigation of the effects of antidepressant medication and one night of total sleep deprivation on cerebral metabolism in depressed patients. This study was undertaken to confirm previous correlations between symptom improvement ratings and regional changes in glucose metabolism, using a higher resolution scanner than in previous investigations. In addition, we also studied the effect of concomitant antidepressant medication in conjunction with sleep depression.
Method: Six depressed patients were administered the selective serotonin reuptake inhibitor sertraline for a week and then underwent positron emission tomography (FDG PET) before and after sleep deprivation. Changes in relative glucose metabolism were correlated with symptom improvement ratings in Hamilton Depression Rating Scale scores.
Results: Positive correlations (defined as reduced HDRS scores associated with areas having reduced relative cerebral glucose metabolism after TSD) were found in the inferior frontal gyrus and inferior frontal/orbital frontal cortex. Negative correlations (defined as reduced HDRS scores associated with areas of increased relative cerebral glucose metabolism after TSD) were found in the dorsolateral prefrontal cortex.
Limitations: Limitations of this study are that the number of subjects was small (n=6) and they were scanned at a 7.6 mm resolution.
Conclusions: The results of this study support previous findings on the effects of sleep deprivation and antidepressant medications in the treatment of unipolar and bipolar depression, with an emphasis on the significance of cerebral glucose metabolic changes in the ventral and DLPF cortex in mood regulation.