How long must symptoms be present to diagnose persistent depressive disorder in adults?

To diagnose persistent depressive disorder (also known as dysthymia) in adults, symptoms must be present for at least two years. This long duration distinguishes persistent depressive disorder from major depressive disorder, where symptoms can be diagnosed after a shorter duration. The requirement of two years reflects the chronic nature of persistent depressive disorder, emphasizing that it often represents a more enduring form of depression. Individuals may experience periods of more severe depressive episodes, but the continuous low mood and other symptoms must persist for the full two years to meet the diagnostic criteria. This extended timeframe helps ensure that the diagnosis accurately captures the patient's ongoing emotional status rather than transient feelings of sadness or depressive symptoms.