a chronic mood disorder characterized by persistent low or depressed mood lasting at least two years in adults (one year in children and adolescents). Symptoms are usually less severe than in a major depressive episode, but are long-lasting and can disrupt daily functioning, including feelings of sadness, decreased energy, decreased concentration, low self-esteem, sleep and appetite disturbances. It is often combined with other mental disorders and increases the risk of developing severe depressive episodes. Treatment includes psychotherapy, medication, or a combination of both.