Cerebral perfusion in chronic fatigue syndrome and depression

Background Patients with chronic fatigue syndrome (CFS) and depressive illn ess share many. but not all, features. Aims To test the hypothesis that patients with CFS have abnormal cerebral p erfusion, that differs from that in patients with depressive illness. Method We recruited 30 patients with CFS who were not depressed, 12 depress ed patients and 15 healthy volunteers. Regional cerebral perfusion at rest was assessed using region of interest (ROI) and voxel-based statistical par ametric mapping (SPM) techniques. Results On SPM analysis there was increased perfusion in the right thalamus , pallidum and putamen in patients with CFS and in those with depressive il lness. CFS patients also had increased perfusion in the left thalamus. Depr essed patients differed from those with CFS in having relatively less perfu sion of the left prefrontal cortex. The results were similar on ROI analysi s. Conclusions Abnormal cerebral perfusion patterns in CFS subjects who are no t depressed are similar but not identical to those in patients with depress ive illness. Thalamic overactivity may be a correlate of increased attentio n to activity in CFS and depression; reduced prefrontal perfusion in depres sion may be associated with the greater neuropsychological deficits in that disorder, Declaration of interest Study funded by the Scottish Home and Health Depart ment and the Wellcome Trust.