In psychotic disorders, such as schizophrenia, altered Dyn/KOR signaling may be one factor that contributes to the dysfunction of dopaminergic transmission in mesolimbic and mesocortical circuitry, which mediate various features of positive and negative symptoms, and cognitive deficits [see Tejeda et al. (2012), Clark and Abi-Dargham (2019)]. Here, OPRK1 is linked to schizophrenia.