Depression is a complex mood disorder marked by persistent feelings of sadness, hopelessness, and a lack of interest in activities. It can disrupt daily functioning by impairing one’s ability to work, sleep, eat, and enjoy life. The causes of depression are multifaceted, involving genetic, biological, environmental, and psychological factors. Symptoms vary but often include changes in sleep, appetite, energy level, concentration, daily behavior, or self-esteem. Depression can be a debilitating condition, but with effective treatment, many individuals find relief and improvement in their symptoms.