Dysthymia, also called dysthymic disorder, is a form of depression. It is less severe than major depression, but usually lasts longer. Many people with this type of depression describe having been depressed as long as they can remember, or they feel they are going in and out of depression all the time.
The symptoms of dysthymia are similar to those of major depression, though they tend to be less intense. In both conditions, a person can have a low or irritable mood, a decrease in pleasure, and a loss of energy. They feel relatively unmotivated and disengaged from the world. Appetite and weight can increase or decrease. The person may sleep too much or have trouble sleeping. He or she may have difficulty concentrating. The person may be indecisive and pessimistic and have a poor self-image.
Symptoms can grow into a full-blown episode of major depression. This situation is sometimes called "double depression" because the second problem (major depressive episode) is superimposed on the usual feelings of low mood. People with dysthymia have a greater-than-average chance of developing major depression.