DRD2 and obesity due to melanocortin 4 receptor deficiency: Following Blum’s initial conceptualization of RDS in 1995, Blum et al. used the Bayesian Theorem [16] to find that carriers of the DRD2 A1 allele had a predictive value of 74.4% for future RDS behaviors such as substance use disorder (SUD), obesity, and shopping addiction.