To this end, we investigated mGluR5 in non-smoking male patients recovering from alcohol use disorder and healthy non-smoking male controls, employing PET with the mGluR5-specific radiotracer 3-(6-methyl-pyridin-2-ylethynyl)-cyclohex-2-enone-O-11C-methyl-oxime ([11C]ABP688).20,21 We compared mGluR5 binding between patients and controls throughout the brain, with a focus on the nucleus accumbens and the amygdala. The gene discussed is GRM5; the disease is alcohol abuse.