DRD2 methylation is closely related to children’s psychological trauma (Cespedes et al., 2021) and alcohol dependence (Shirvani-Farsani et al., 2021) and is a marker of schizophrenia (Gangisetty et al., 2015; Molitch, 2020; Lisoway et al., 2021) showed that increased DRD2 promoter methylation is correlated with decreased DRD2 mRNA levels and increased PRL mRNA levels in the pituitary. This evidence concerns the gene PRL and schizophrenia.