It is not a passing sad mood. People with major depression often feel sad, helpless, hopeless, and irritable. It is the persistence and severity of these emotions that distinguishes clinical depression from normal mood changes.
Depression usually begins in adolescence or early adulthood.
It is often not recognized, and thus people who have it may suffer for years without proper diagnosis or treatment. Symptoms and their severity vary with each individual case of depression. The highest rates of depressive disorders are found among those aged 24-44, and the rate of clinical depression for women is about double that of men. Studies show that depression underlies the majority of suicides, is the eighth leading cause of death, and is the third leading cause of death among people aged 15-24. One of the best strategies for preventing suicide is the early recognition and treatment of depression.