KOR activation and administration of KOR agonists including salvinorin A may induce hallucinations, anxiety, depression, negative-like symptoms (lack of motivation and social withdrawal), psychomotor retardation, dysphoria and neurocognitive impairments including in attention, working memory and task performance, which are quite similar to the effects of acute ketamine administration [81,82,83]. This evidence concerns the gene OPRK1 and depressive disorder.