Objective: To investigate whether alcohol-related disorders affect cerebral blood flow at baseline and while concentrating. Method: Subjects were selected from an archival de-identified database including 1075 individuals diagnosed with alcohol-related disorders and 93 healthy individuals. Participants were given a SPECT scan both at rest (baseline) and while taking the CPT (concentration). The alcohol sample included 815 males (69.8%) and 353 (30.2%) females with an average age of 38.84 (SD = 14.45). Results: At the .01 level, t-tests revealed statistically significant differences. During baseline, healthy individuals had increased cerebral blood flow in right and left hemispheric limbic system as well as right and left hemispheric basal ganglia. During concentration, healthy individuals had increased cerebral blood flow in right and left hemispheric limbic system, right and left hemispheric basal ganglia, and right and left hemispheric motor-sensory as well as in the vermis. Conclusion: The SPECT imaging reveals that long-term alcohol use may result in changes in the brain resulting in decreased activity in some areas of the brain, but not all. The results suggest that individuals with a history of chronic alcohol use have decreased activity in a greater number of brain regions during concentration. Alcohol appears to have greater long-term effect on the posterior and subcortical regions. The differences are found in areas of the brain that would affect skills such as reaction times and coordination. Alcohol use appears to have a long-term effect even when the person is no longer drinking.