Evaluation of the dopaminergic system with positron-emission tomography in alcohol abuse: A systematic review

•Decrease in D2 receptor in different brain regions in human alcoholics.•Decrease in D3 receptor in different brain regions in human alcoholics.•Dopaminergic system plays an important role in the pathophysiology of alcoholism. Performed a systematic review to evaluated the dopaminergic system in alcohol abuse in a systematic review in humans. A search of the electronic databases was proceeded, on MEDLINE, EMBASE, Cochrane Library, Insight and Gray literature (Google Scholar and the British Library) for studies published until August 2018. A search strategy was developed using the terms: “dopamine” and “ethanol” or ““alcohol”,” and “positron-emission tomography” as text words and Medical Subject Headings (i.e., MeSH and EMTREE) and searched. We found 293 studies. After reading titles and abstracts 235 were considered irrelevant, as they did not meet the inclusion criteria. For the reading of the full text, 50 studies were analyzed. Of these 41 were excluded with reasons by study design, patient population, intervention and outcomes. Nine studies were included in our qualitative synthesis. Four studies have resulted in a reduction in availability only at the D2 receptor in different brain regions. Concerning the D3 receptor alone only one study reported this finding and four studies reported a decrease in both receptors. Changes in D2 receptors in several brain regions in human alcoholics were found in a systematic review.