Signs and symptoms of depression may include persistent feelings of sadness, loss of interest or pleasure in activities, changes in appetite or sleep patterns, fatigue, irritability, and difficulty concentrating. Treatment for depression may involve therapy, medication, lifestyle changes, and support services.Signs and symptoms of depression may include persistent feelings of sadness, loss of interest or pleasure in activities, changes in appetite or sleep patterns, fatigue, irritability, and difficulty concentrating. Treatment for depression may involve therapy, medication, lifestyle changes, and support services.