The development of human brain imaging has resulted in a number of techniques that allow unprecedented insights into the in vivo metabolic and neurochemical processes of the brain. Single positron emission cerebral tomography (SPECT) is a nuclear medicine technique that can be used for measuring perfusion and blood flow in patients affected with psychopathology. The aim of the study was to compare sole depressed patients and those with comorbid alcohol dependence in terms of the functional alterations detected by single positron emission scan (SPECT). For this, 27 SPECT imaging studies performed at Hospital Clínico Pontificia Universidad Católica, of selected patients, were collected and categorized by group. First group composed by depressed patients and second group of patients having alcohol dependence in addition to depression. Selected studies were corregistered, normalized and smoothed for standarization before statistic analysis was performed using MatLan7.1 software with SPM5 module. Mean blood flow in brain areas were compared between groups, with significant statistical difference at p<0.01.

Results show significantly less blood flow in the group with alcohol dependence in Brodmann Areas 4,6,8,9,45and46 of the frontal lobe and BrodmannAreas 2,3,4,5,7and40 of the parietal lobe (p<0.01). Furthermore, the group with alcohol dependence showed increased blood flow in frontal lobe's Brodmann Area 10, temporal lobe's Brodmann Areas 13,20,22, cerebellum, uncus and thalamus.(p<0.01). We conclude that alcohol dependence as comorbid condition in depressed patients determines an additional decrease in the mean blood flow of prefrontal and temporal lobes.