Depression Definition: Depression is commonly defined as a mental illness in which a person experiences deep sadness, melancholy and reduced interest in most activities that they were previously interested in. The term depression is also used to describe the temporary sadness or loneliness that many people feel from at various times throughout the lifespan. In contrast to normal sadness, severe depression, or major depression, can dramatically weaken a person’s ability to function appropriately in social situations. Those who suffer from major depression often experience feelings of despair, hopelessness and worthlessness.   While depression is a common illness, effective treatment improves the lives of many sufferers. Depression occurs all around the world, although symptoms vary.  Statistics indicate that depression rates are increasing around the world, with younger generations being diagnosed at an earlier age than previous generations.  Depression can occur at any time in a person’s life however it is most common during a person’s 20s or 30s.  Depression can occur gradually over time or suddenly in a matter of days or weeks.