Dysthymia, or low-grade depression, is less severe than major depression but more chronic. It occurs twice as often in women as in men.
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.
The main sign of dysthymia is low, dark, or sad mood nearly every day for at least two years. Other symptoms can include:
In dysthymia, these symptoms are not directly a result of a general medical condition or use of substances; in addition, they result in impaired functioning in work, social or personal areas.
Although its exact cause is unknown, dysthymia appears to have its roots in a combination of genetic, biochemical, environmental and psychological factors. In addition, chronic stress and trauma can provoke dysthymia.
Stress is believed to impair one's ability to regulate moods and prevent mild sadness from deepening and persisting. Social circumstances, particularly isolation and the unavailability of social support, also contribute to dysthymia. 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 old age, dysthymia is more likely to be the result of medical illness, cognitive decline, bereavement, and physical disability. 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.
Research indicates that depressive illnesses are disorders of the brain. Brain-imaging technologies, such as magnetic resonance imaging (MRI), 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 behavior 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.
Many people with dysthymia 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 dysthymia believe their symptoms are an inevitable part of life. In older people, dementia, apathy, or irritability can disguise dysthymia. Asking open-ended questions—such as "How are things at home?"—can help a physician begin to notice the signs of dysthymia.
Like major depression, dysthymia can be treated with supportive therapy that provides advice, reassurance, sympathy, and education. Like the process of learning, which involves the formation of new connections between nerve cells in the brain, psychotherapy works by changing the way the brain functions. Certain types of psychotherapy including supportive therapy, cognitive-behavioral therapy (CBT), psychodynamic therapy and interpersonal therapy (IPT), can help relieve dysthymia. Supportive therapy provides advice, reassurance, sympathy, and education about the disorder. CBT helps identify and change the negative styles of thinking that promote self-defeating attitudes and behaving that improves social skills and teaches ways to manage stress and unlearn learned helplessness. Psychodynamic therapy helps patients resolve emotional conflicts, especially those derived from childhood experience. IPT helps patients to cope with personal disputes, loss and separation, and transitions between social roles. Preliminary evidence from an ongoing NIMH-supported study indicates that IPT, in particular, may hold promise in the treatment of this disorder.
As with other forms of depression, there are a number of medication options for people with dysthymia. The most common drug treatments include selective serotonin reuptake inhibitors like fluoxetine (Prozac) and sertraline (Zoloft), or one of the newer dual-action antidepressants such as venlafaxine (Effexor). Some patients may respond to tricyclic antidepressants such as imipramine (Tofranil). Antidepressant drugs have a number of side effects that can complicate treatment. For example, SSRIs may cause stomach upset, mild insomnia, and reduced sex drive.
For many patients, a long-term combination of medication and psychotherapy that includes a solid relationship with a mental health professional is the most effective course of treatment. Recovery from dysthymia can take a long time, and the symptoms often return. For this reason, many patients are encouraged to continue doing whatever made them well—whether it was a drug, therapy, or a combination of the two—after recovery.