In this R13 application we request support for the 4th Gordon Research Conference (GRC) on “Neurobiology of Drug Addiction,” taking place in May 2026 in Castelldefels, Spain. The objectives of this GRC are to foster open discussion of novel research developments, build new collaborations, and propel the next generation of both scientific advances in addiction research and addiction neuroscience researchers. To achieve these objectives, we will pursue the following four specific aims at the meeting: 1) To create an international forum that will promote deeper understanding of the neurobiology of addiction, based on groundbreaking findings from basic science, clinical, and community focused research; 2) Introduce novel and emerging research techniques to facilitate understanding of drug addiction; 3) Promote interdisciplinary interactions amongst addiction researchers, stimulating the exchange of ideas and collaborations that will advance the field of addiction research; and 4) Foster the development of the next generation of addiction researchers by facilitating and encouraging the participation of students, postdoctoral fellows, and early career investigators. The conference focuses on presentations and discussions at the frontiers of addiction research. The scope of the lectures will be confined to basic and clinical studies involving addictive drugs (including alcohol) and the nervous system and will focus on mechanisms of compulsive drug use, relapse, and vulnerability to addiction. The meeting will also break down barriers to progress by uniting investigators with synergistic and complementary expertise in areas ranging from molecular mechanisms to translational clinical research, community focused research, and addiction theory. The conference will provide a forum to address the latest developments in addiction research in an open and highly interactive GRC format, which includes formal talks interspersed with ample discussion time, poster sessions, and informa