Depression Depression is when a person is in a melancholy state. In the Encyclopedia Americana depression is defined as a normal response to a sense of loss, “but when the depression is unrelated to any actual event or is grossly excessive in portion to its apparent cause, then it reflects some form of mental illness" (747). It is very unclear whether depression is produced by the psychological experience or by the chemical imbalance in the brain. These unexplained factors involving the cause of depression, and the wide range of effects that depression produces, make it a sophisticated mental illness to diagnose. Depression has been documented since the ancient times. The Magill’s Medical Gu