[Biomarkers for Mood Disorders and a Novel Antidepressant (R)-ketamine].

Depression is often misdiagnosed as major depressive disorder in patients with bipolar disorder. Therapeutic drugs for these two disorders are quite different, but the anesthetic ketamine shows fast-acting antidepressant effects in treatment-resistant patients with these disorders. Here, we discuss biomarkers for both disorders, recent findings regarding ketamine, and predictable biomarkers for ketamine's antidepressant actions.