Depression is a mood disorder marked by persistent feelings of sadness, hopelessness, or loss of interest that affect daily life and overall functioning. It can influence emotions, thoughts, energy levels, sleep, and appetite, making even routine activities feel overwhelming. Depression may also impact concentration, motivation, and self-esteem, often leading to social withdrawal or emotional distress. With proper assessment and evidence-based treatment, individuals can gain insight into their condition, build effective coping skills, and move toward improved emotional health and quality of life.