In comparison, kappa opioid receptor (KOR) agonists do not have rewarding effects (Vonvoigtlander et al., 1983), and are not associated with respiratory depression (Freye et al., 1983) or gastrointestinal transit (Porreca et al., 1984), and have potential to treat pain (Beck et al., 2019; Paton et al., 2020a). The gene discussed is OPRK1; the disease is Respiratory insufficiency due to muscle weakness.