We all have better and worse days. Frustration, sadness, resentment, irritability, or depression are usually feelings that you try to avoid. However, these are normal reactions to the daily setbacks or frustrations that everyone has to face from time to time. Most of the time, these feelings go away in a few days and are again replaced by emotions we like, such as joy, pleasure, satisfaction or the will to act. However, the mood does not always improve and the person feels sad, anxious, powerless or worthless for weeks or even months. In this case, it is no longer a matter of short-term normal sadness or bad mood, but depression. Depression is a disease that does not go away on its own, it must be treated like any other disease.