In the DSM-5, dysthymia was replaced with a condition called "persistent depressive disorder," which includes both chronic major depressive disorder and the previous dysthymic disorder. This condition is a chronic form of depression that is milder than major depression.

Persisitent depressive disorder is characterized by the presence of depressed mood for most of the day, for more days than not, over a period of at least two years. It may be intermittent and interspersed with periods of feeling normal, but these periods of improvement last for no more than two months.

Dysthymia, or persistent depressive disorder, is believed to be twice as common in women as in men. People who have the condition before age 21 tend to have a higher incidence of personality disorders. Because the onset of symptoms is insidious, persistent depressive disorder often goes unnoticed. And because of its chronic nature, the person may come to believe, "I've always been this way." In addition to depressed mood, symptoms include two or more of the following:

  • poor appetite or overeating
  • insomnia or hypersomnia (excessive sleeping)
  • low energy or fatigue
  • low self-esteem
  • poor concentration or difficulty making decisions
  • feelings of hopelessness.

It is far better to treat dysthymia than to think of it as a minor condition, according to a recent seven-year prospective study of more than 1,000 young people in New Zealand. Bypassing treatment places people at increased risk for subsequently developing major depression. In fact, about 10 percent of people with persistent depressive disorder also have recurrent episodes of major depression, a condition known as double depression.

Biological Causes of Persistent Depressive Disorder

Some medical conditions, including neurological disorders (such as multiple sclerosis and stroke), hypothyroidism, fibromyalgia, and chronic fatigue syndrome, are associated with dysthymia. Investigators believe that, in these cases, developing the condition is not a psychological reaction to being ill but rather is a biological effect of these disorders.

There are many reasons for this connection—it may be that these medical conditions interfere with the action of neurotransmitters, or that medications (such as corticosteroids or beta-blockers) taken for a medical illness may trigger the dysthymia, or that both persistent depressive disorder and the medical illness are related in some other way, reinforcing each other in a complicated manner.

Dysthymia can also follow severe psychological stress, such as losing a spouse or caring for a chronically ill loved one. Older people who have never had psychiatric disorders are particularly susceptible to developing persistent depressive disorder after significant life stresses.

Updated by Remedy Health Media

Publication Review By: Karen L. Swartz, M.D.

Published: 01 Mar 2011

Last Modified: 02 Dec 2014