It is suggested to be a sex-specific risk factor in bipolar affective disorder, major depressive disorder, and schizophrenia.495 GPR50 can antagonize the MT1 receptor by forming a heterodimer.496 The inhibitory effects are mediated via the large C-terminal tail, which blocks the β-arrestin recruitment and G protein coupling.495 MT2 receptor could also form a heterodimer with GPR50, but the functional consequence remains to be defined.496. Here, GPR50 is linked to bipolar disorder.