Dysthymia is a serious and disabling disorder that shares many symptoms with other forms of clinical depression. It is generally experienced as a less severe but more chronic form of major depression.
Dysthymia is characterized by depressed mood experienced most of the time for at least two years, along with at least two of the following symptoms: insomnia or excessive sleep, low energy or fatigue, low self-esteem, poor appetite or overeating, poor concentration or indecisiveness, and feelings of hopelessness. The more severe symptoms that mark major depression, including anhedonia (inability to feel pleasure), psychomotor symptoms (particularly lethargy or agitation), and thoughts of death or suicide, are often absent in dysthymia.
Dysthymia can occur alone or in conjunction with other mood or psychiatric disorders. For instance, more than half of people who suffer from dysthymia will experience at least one episode of major depression; this condition is known as double major depressive disorder.
Dysthymia is about as common as major depression, affecting about 6 percent of the US population. Like major depression, dysthymia occurs twice as often in women as in men.