KOR agonists may also be useful for treatment and prevention of opioid or cocaine use disorders (Simonson et al., 2015; Townsend et al., 2017; Kivell et al., 2018; Zamarripa et al., 2020b,2021) and for treatment of demyelinating diseases (Du et al., 2016; Denny et al., 2021; Dworsky-Fried et al., 2021; Paton et al., 2021). Here, OPRK1 is linked to demyelinating disease.