The consistent finding during recent years that the DRD2 gene is a top candidate with significant associations in candidate and GWAS studies involving millions of people presenting with depression, suicide ideation, and attempted suicide, as well as SUD, provides enough evidence to satisfy the scientific community to disembark from the previous controversy related to whether this gene and associated polymorphisms are indeed linked to most if not all substance and non-substance behavioral addictions. This evidence concerns the gene DRD2 and major depressive disorder.