 What is a depression? Depression is a common and serious medical illness that negatively affects how you feel, the way you think and how you act. Fortunately, it is also treatable. Depression causes feelings of sadness and or a loss of interest in activities once enjoyed. It can lead to a variety of emotional and physical problems and can decrease a person's ability to function at work and at home. Depression symptoms can vary from mild to severe and can include changes in appetite, weight loss or gain unrelated to dieting, trouble sleeping or sleeping too much, feeling worthless or guilty, difficulty thinking, concentrating or making decisions, thoughts of death or suicide. Symptoms must last at least two weeks for a diagnosis of depression. Also, medical conditions for example thyroid problems, a brain tumor or vitamin deficiency can mimic symptoms of depression so it is important to rule out general medical causes. Depression is among the most treatable of mental disorders. Between 80% and 90% of people with depression eventually respond well to treatment. How to reduce the symptoms of depression? Regular exercise helps create positive feeling and improve mood. Getting enough quality sleep on a regular basis, eating a healthy diet and avoiding alcohol can also help re-reduce symptoms of depression.