Depression is a mental illness characterized by persistent feelings of sadness and a lack of interest in activities. It affects over 20% of people globally and rates are even higher in Pakistan, where 34-53% of people in major cities suffer from depression. Depression can cause a variety of symptoms from mild to severe, including feelings of hopelessness, changes in appetite and sleep, and inefficient thinking. It has multiple causes like heredity, medical conditions, life stressors, and unemployment. Treatment options include medication, therapy like CBT to change negative thought patterns, lifestyle changes like exercise and diet, and interpersonal therapy to help understand relationships.