To provide: an agent for the prevention and/or treatment of a depressive symptom, the drug consisting of (S)-norketamine or a pharmacologically acceptable salt thereof； a pharmaceutical composition for the prevention and/or treatment of a depressive symptom, the pharmaceutical composition containing (S)-norketamine or a pharmacologically acceptable salt thereof in an amount effective for alleviation of the depressive symptom, and being substantially free of (R)-norketamine； a method for the prevention and/or treatment of a depressive symptom, the method including administration of the drug or the composition； and use of (S)-norketamine for production of a drug for the prevention and/or treatment of a depressive symptom or a composition for the prevention and/or treatment of a depressive symptom.
