Depression causes sadness or loss of interest or enjoyment of life to a degree that interferes with daily activities. It is a medical condition, not a normal reaction to such life situations as the death of a loved one or the loss of a job. About 1 of every 5 people experiences depression at some time in his or her life, and it is common among patients who see primary care providers. Common symptoms are lack of energy, change in sleep or appetite, and prominent thoughts of worthlessness or guilt. Sometimes the condition goes away on its own, but many depressed people need treatment with counseling or medication to speed recovery. Often, people with depression do not realize that their feelings are caused a medical condition and do not seek medical care. Although depression is associated with poor health outcomes, the prognosis for people with symptoms of mild depression (which is sometimes called subsyndromal depression) have not been well described.