Dysthymia is less severe than major depressive disorder, but it is more chronic. In dysthymia, a depressed mood along with at least two other symptoms of depression persist for at least two years in adults, or one year in children or adolescents. These symptoms may not be as disabling, but they do keep affected people from functioning well or feeling good. Dysthymia often begins in childhood, adolescence, or early adulthood. On average, untreated dysthymia lasts four years in children and adolescents.