Depression is a condition that many people suffer from at different points in their lives. It is usually marked by a feeling of continuous despair, low mood, and disinterest in normally enjoyable activities.
There are a variety of causes for depression, and one can be afflicted by it for weeks, months, and even years. Depression can lead to suicidal thoughts.
If you or someone you know suffers from depression or you/they are at risk for harming yourself/themselves because of depression, it is highly recommended that you seek help or treatment for it.