Design: This study has two phases (phase I and II). The two phases can be done as inpatient (AD subjects) or as outpatient (AD and healthy controls) over a 2-3 day period. In phase I participants will undergo two positron emission tomography (PET) scans, one with [11C]PBR28 (marker of neuroinflammation) and one with 18FDG (marker of brain glucose metabolism) and magnetic resonance imaging (MRI) scans to assess brain structure, functional reactivity and functional connectivity. In parallel we will perform neuropsychological tests (NP). Phase II will include the same procedures as Phase I but it will be done about 3 weeks later over a 2-3 day period only in the participants (alcoholics or controls) who in Phase I show evidence of inflammatory changes. In AD participants Phase II will be done after alcohol abstinence and in healthy controls it will be repeated with no intervention. We will complete studies on at least ten alcoholic users (n=10) before we can feel confident that there is no neuroinflammation. In parallel we need to collect data on at least ten (n=10) controls so we have a comparison group scanned under the same characteristics as the alcoholics to do this preliminary investigation.