This document provides an overview of anti-depressant agents, including what depression is, different types of depression, how anti-depressant drugs work, common therapeutic classes, treatment considerations, and drug interactions. It discusses how anti-depressants affect neurotransmitters to treat conditions like depression, obsessive-compulsive disorder, and panic disorders. Common classes mentioned are tricyclic antidepressants, SSRIs, MAOIs, and newer second and third generation drugs.