Dysthymia Disorder

Dysthymia is a mild but long term (chronic) form of depression, symptoms last a long time up to two years and you suffer many high and low periods of depression. Dysthymia interferes with your entire life.

When Dysthymia starts before age 21 its called early on set Dysthymia, when it starts in adulthood its called late on set Dysthymia.

Mayo Clinic