You can read the abstract of this article at The idea of Reward Deficiency Syndrome suggests that addiction to various substances occurs because they stimulate the brains reward system so intensely that the population of dopamine D2 receptors (DD2R) decreases
doi:10.1177/1553350613505918 Lexicomp
doi: 10.3390/ijms20184559 Summary Keywords thiamine, riboflavin, niacin, pyridoxine, folate, cobalamin, complex B vitamins, neuropsychiatric manifestations Citation Han A, Almeida L, Anand N, Salloum IM, Kanaan S, Gadad BS and Daher JPL (2025) Exploring neuropsychiatric manifestations of vitamin B complex deficiencies
Satyanarayana K, Sravanthi K, Shaker IA, Ponnulakshmi R