A depressive disorder is an illness that involves the body, mood, and thoughts. It affects the way a person eats and sleeps, the way one feels about oneself, and the way one thinks about things. A depressive disorder is not the same as a passing blue mood.

Depressive disorders come in different forms. The three most common types of depressive disorders are major depression, dysthymia and bipolar disorder.

Major depression is manifested by a combination of symptoms that interfere with the ability to work, study, sleep, eat, and enjoy once pleasurable activities. Such a disabling episode of depression may occur only once but more commonly occurs several times in a lifetime. Dysthymia, a less severe type of depression, involves long-term, chronic symptoms that do not disable, but keep one from functioning well or from feeling good. Many people with dysthymia also experience major depressive episodes at some time in their lives.

Bipolar disorder is another type of depression also called manic-depressive illness. Not nearly as prevalent as other forms of depressive disorders, bipolar disorder is characterized by cycling mood changes: severe highs (mania) and lows (depression). Sometimes the mood switches are dramatic and rapid, but most often they are gradual.In the past few years, much interest has risen in the use of vitamins and herbs in the treatment of depression. Several studies have shown that taking SAMe is superior to a placebo for reducing symptoms of depression. St. John's wort may relieve the symptoms of depression in people who suffer from mild to moderate depression. Taking 5-HTP seems to improve symptoms of depression. 5-HTP can increase synthesis of serotonin. Deficiencies of serotonin in the brain have been linked to depression. Folic acid deficiency is common among people with depression. Low folate levels have been linked to poor response to antidepressant treatment.The first step to getting appropriate treatment for depression is a physical examination by a physician. Treatment choice will depend on the outcome of the evaluation. There are a variety of antidepressant medications and psychotherapies that can be used to treat depressive disorders.

Anyone who has depression that is serious enough to require treatment should talk to a doctor before taking any of these supplements.