Persistent depressive disorder or dysthymia is a recurrent depressive disorder with no clearly demarcated episodes. Onset is insidious and can occur in adolescence or adulthood. Dysthymia frequently remains unrecognized and undiagnosed for years. Co-morbid major depression, anxiety, personality, somatoform and substance abuse disorders are common. Symptoms center on sad mood, pessimism and hopelessness. Sufferers experience significant functional impairment and are at risk of death by suicide. Those most at risk are female, unmarried, live in high income countries and have family histories of depression. Screening instruments include the Cornell Dysthymia Rating Scale (CDRS). Typical treatments are antidepressant medications and cognitive behavioral analysis system of psychotherapy (CBASP). This paper provides health professionals with an overview of assessment and treatment approaches in dysthymia.