Persistent Depressive Disorder (PDD), also known as dysthymia, is a long-term form of depression characterized by a consistently low mood that lasts for at least two years in adults (or one year in children and adolescents). Unlike major depressive disorder, the symptoms of PDD may be less severe but are more chronic, often including feelings of sadness, low energy, poor self-esteem, difficulty concentrating, and changes in sleep or appetite.
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