An antidepressant is a medication that is designed to help alleviate symptoms of depression, such as feelings of sadness or hopelessness. These drugs work by affecting the levels of certain chemicals in the brain that are associated with mood regulation and can help improve mood and reduce anxiety. Antidepressants come in different types and classes, including selective serotonin reuptake inhibitors (SSRIs), serotonin-norepinephrine reuptake inhibitors (SNRIs), tricyclic antidepressants (TCAs), and monoamine oxidase inhibitors (MAOIs). They are typically prescribed by a doctor and taken over the course of several weeks or months to achieve the desired effect.