What are the mechanisms of action of current antidepressant treatments?

An array of antidepressant medications is available, but many patients do not achieve remission of their depressive episodes with initial treatment. Antidepressants differ in their mechanisms of action, with most of their therapeutic effects believed to be related to their effects on serotonin, norepinephrine, and/or dopamine. Depressive symptoms can vary greatly from patient to patient, and, therefore, different medications may be effective for one individual and not another. Clinicians can optimize treatment by selecting the antidepressant agent with the mechanism of action most likely to alleviate each patient's individual symptom profile. Here, follow the case of Randal, a 62-year-old surgeon with a treatment-resistant depressive episode.