Is the antidepressant efficacy of ketamine and esketamine mediated via opioid mechanisms?
European Psychiatry January 1, 2026 Andy Lu, Heidi Xu, Gia Han Le et al. 4 citations
Ketamine's antidepressant effects in treatment-resistant depression may be partially mediated by the opioid system, but the evidence is mixed. Because opioid receptor antagonists inconsistently reduce these effects, the opioid system likely acts as a context-dependent modulator rather than a primary mediator, especially at standard antidepressant doses.