When plasma oxytocin levels were previously measured in patients with schizophrenia, conflicting results were obtained, that is, lower or higher levels of oxytocin or even no change relative to healthy participants (Beckmann et al., 1985; Glovinsky et al., 1994; Goldman et al., 2008; Strauss et al., 2019). The gene discussed is OXT; the disease is schizophrenia.