The condition characterized by persistent feelings of sadness and loss of interest is known as depression. It affects daily functioning and can lead to significant emotional and physical distress. Symptoms often include a lack of energy, difficulty concentrating, changes in appetite, and disrupted sleep patterns. Depression is linked to various factors, including genetic predisposition, biochemical imbalances, and environmental stressors. Treatment commonly involves a combination of therapy, medication, and lifestyle changes aimed at improving mental well-being. Early intervention is crucial for better prognosis and recovery.