Persistent depressive disorder (dysthymia) is a form of depression. It may be less severe than major depression, but — as the name suggests — it 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 persistent depressive disorder are similar to those of major depression. In this disorder, the long duration is the key to the diagnosis, not the intensity of symptoms. As with major depression, mood may be low (or irritable in children and adolescents). An individual with persistent depressive disorder may feel less pleasure and a lack of energy. He or she may feel relatively unmotivated and disengaged from life. Appetite and weight can increase or decrease. The person may sleep too much or have trouble sleeping. Indecisiveness, pessimism and poor self-image may also be present.
Symptoms can grow into a full-blown episode of major depression. People with persistent depressive disorder have a greater-than-average chance of developing major depression.
While major depression often occurs in episodes, persistent depressive disorder is defined as more constant, lasting for years. The disorder sometimes starts in childhood. As a result, a person with persistent depressive disorder tends to believe that depression is part of his or her character, and so self-defining that he or she may not even think to talk about this depression with doctors, family members or friends.
Persistent depressive disorder, like major depression, tends to run in families. It is more common in women than in men, but in men it may be underdiagnosed because men are less likely to talk to their doctors about their mood. Some people with persistent depressive disorder have experienced a major loss in childhood, such as the death of a parent. Others describe being under chronic stress. But it is often hard to know whether people with the disorder are under more stress than other people or if the disorder causes them to perceive more stress than others do.
Symptoms
The main symptom of persistent depressive disorder is a long-lasting low or sad mood. Children and adolescents with persistent depressive disorder may be irritable. Other symptoms include:
- increased or decreased appetite or weight
- lack of sleep or sleeping too much
- fatigue or low energy
- low self-esteem
- difficulty concentrating
- indecisiveness
- hopelessness or pessimism.
Causes
Persistent depressive disorder appears to have its roots in a combination of genetic, biochemical, environmental, and psychological factors. In addition, chronic stress and trauma can provoke PDD.
Stress is believed to impair one’s ability to regulate mood and prevent mild sadness from deepening and persisting. Social circumstances, particularly isolation and the unavailability of social support, also contribute to the development of PDD. This cause can be especially debilitating given that depression often alienates those who are in a position to provide support, resulting in increased isolation and worsening symptoms. In addition, trauma, loss of a loved one, a difficult relationship, or any stressful situation may trigger a depressive episode. Subsequent depressive episodes may occur with or without an obvious trigger. In old age, PDD is more likely to be the result of medical illness, cognitive decline, bereavement and physical disability.
Research indicates that depressive illnesses are disorders of the brain. Brain-imaging technologies, such as magnetic resonance imaging, have shown that the brains of people who have depression look different than those of people without depression. The parts of the brain responsible for regulating mood, thinking, sleep, appetite, and behaviour appear to function abnormally. In addition, important neurotransmitters—chemicals that brain cells use to communicate—appear to be out of balance. But these images do not reveal why the depression has occurred.
Are dysthymia and cyclothymia similar?
Dysthymia, or persistent depressive disorder, is mild chronic depression. Cyclothymia is a mild case of bipolar disorder. A person with cyclothymia might be mildly depressed at one moment, then mildly manic at another moment.
Treatment
Psychotherapy
Many people with persistent depressive disorder do not get the treatment they need; in many cases because they only see their family doctors, who often fail to diagnose the disorder. Part of the problem is that people suffering from PDD believe their symptoms are an inevitable part of life. In older people, dementia , apathy, or irritability can disguise PDD. Open-ended questions are helpful: “How has your mood been recently?”
