Depression is classified as a mood disorder characterized by feelings of sadness, loss, or anger that interfere with daily life. However, feeling down at times is normal, but feeling this way regularly could indicate depression. Symptoms include changes in mood, behavior, sleep, appetite, energy levels, concentration, and self-esteem. Depression can be situational due to life stresses, related to seasons, or associated with medical conditions and life events like childbirth. Treatment options include antidepressant medication, therapy, lifestyle changes, and supplements. Managing depression is an ongoing process that may require trying different treatment approaches.