Depression may begin with symptoms of anxiety (such as excessive worrying) or symptoms such as sadness or lack of energy that last for days or months before the onset of full-blown depression. You may have trouble concentrating or remembering, experience a loss of pleasure in things you used to enjoy, feel hopeless, and have low energy and changes in sleeping and eating patterns. You may withdraw socially from others and lose interest in sexual activity.

The course of depression varies from one person to another. You might have mild or severe symptoms of depression for a long time, or you may have them for a brief time. A small number of people feel depressed for most of their lives and require ongoing treatment. Most people who have depression can be treated successfully with medication, professional counseling, or a combination of the two.

Depressive disorders are classified according to their severity and duration. Depression may be mild, moderate, or severe. It may start suddenly (acute) or be long-lasting (chronic). Dysthymic disorder, for example, is chronic mild depression. Some people may experience an episode of major depression on top of dysthymic disorder (double depression).

For severe depression, you may need to be admitted to a hospital for a short time, especially if you are having thoughts of suicide. Because depression puts you at a higher risk for attempting suicide, you should seek immediate treatment if you are having self-destructive thoughts.

Recurring illness

Depression often recurs. If you have one episode of depression, you are more likely to become depressed again at some point in your life than someone who has never been depressed. The risk of having another episode of depression increases with each additional episode.³

Related illness

Depressed people who have a chronic illness such as diabetes or coronary artery disease suffer more from symptoms of their illnesses, are less able to function, have a decreased quality of life, and pay more in medical costs. People with depression are less likely to take good care of themselves, and this may make their health worse.⁶

Sometimes episodes of depression are preceded or followed by periods of high energy (mania). If you cycle between depression and mania, you may have a condition called bipolar disorder. For more information, see the topic Bipolar Disorder.

If you have depression only during certain seasons of the year, such as the fall and winter months, you may have seasonal affective disorder. For more information, see the topic Seasonal Affective Disorder (SAD).