Other factors linked with dysthymia include stress, social isolation, and lack of social support.In a study using identical and fraternal twins, results indicated that there is a stronger likelihood of identical twins both having depression than fraternal twins. This provides support for the idea that dysthymia is in part caused by heredity means. Co-occurring conditions
Dysthymia often co-occurs with other mental disorders. A "double depression" is the occurrence of episodes of major depression in addition to dysthymia. Switching between periods of dysthymic moods and periods of hypomanic moods is indicative of cyclothymia, which is a mild variant of bipolar disorder. "At least three-quarters of patients with dysthymia also have a chronic physical illness or another psychiatric disorder such as one of the anxiety disorders, cyclothymia, drug addiction, or alcoholism". Common co-occurring conditions include major depression (up to 75%), anxiety disorders (up to 50%), personality disorders (up to 40%), somatoform disorders (up to 45%) and substance use disorders (up to 50%). People with dysthymia have a higher-than-average chance of developing major depression. A 10-year follow-up study found that 95% of dysthymia patients had an episode of major depression. When an intense episode of depression occurs on top of dysthymia, the state is called "double depression." Double depression
Double depression occurs when a person experiences a major depressive episode on top of the already-existing condition of dysthymia. It is difficult to treat, as patients accept these major depressive symptoms as a natural part of their personality or as a part of their life that is outside of their control.
The symptoms are often not directly caused by a medical illness or by substances, including substance use or other medications. The symptoms may cause significant problems or distress in social, work, academic, or other major areas of life functioning.In children and adolescents, mood can be irritable, and duration must be at least one year, in contrast to two years needed for diagnosis in adults. Early onset (diagnosis before age 21) is associated with more frequent relapses, psychiatric hospitalizations, and more co-occurring conditions. For younger adults with dysthymia, there is a higher co-occurrence in personality abnormalities and the symptoms are likely chronic. However, in older adults with dysthymia, the psychological symptoms are associated with medical conditions and/or stressful life events and losses.Dysthymia can be contrasted with major depressive disorder by assessing the acute nature of the symptoms. Dysthymia is far more chronic (long lasting) than major depressive disorder, in which symptoms may be present for as little as two weeks. Also dysthymia often presents itself at an earlier age than major depressive disorder. Prevention
Though there is no clear-cut way to prevent dysthymia from occurring, some suggestions have been made. Since dysthymia will often first occur in childhood, it is important to identify children who may be at risk. It may be beneficial to work with children in helping to control their stress, increase resilience, boost self-esteem, and provide strong networks of social support. These tactics may be helpful in warding off or delaying dysthymic symptoms. Treatments
Persistent depressive disorder can be treated with psychotherapy and pharmacotherapy.