Causes
Heredity plays a large part in the occurrence of dysthymia. Most people
will have a family history of mood or affective disorders, especially when dysthymia
starts early in life (teens to early 20s).
About one-quarter of people with dysthymia develop the condition in mid-life,
known as late-onset dysthymia. Symptoms usually follow a particular depressive episode, related to some shock or loss a person has experienced.